Overview › Code › R70
Code · blind round

R70 · Binary search, step by step

blind round 9/11 local models answered

Every answer below carries the name of the model that wrote it. Blind refers to the scoring: the review was done without knowing which model produced which answer — the published result names them.

2 of the 11 local models delivered nothing through our test harness in this round — for reasons that lie with our setup, not with the models. Those cards are marked DNF like any other, but they are not evidence about those models — the reason is noted on the card itself.

A frontier reference answered the same task (Claude Opus 5) — outside the field and deliberately unscored, further down the page.

Show task 
Create ONE self-contained HTML file (STRICT LIMIT: max 120 lines total) that animates a binary search on a sorted array of 40 values drawn as labelled bars on a <canvas>. Show the low, high and middle markers, highlight the middle element being compared, and grey out the half that gets discarded in each step. Display the target value and the number of comparisons used. Smooth requestAnimationFrame animation, NO user input, starts immediately and keeps running (restart with a fresh random instance when finished). No external libraries, no comments needed. Output ONLY the HTML file content, nothing else.

The answers

Local models (Brain cluster) — identical prompt, shuffled order (the sequence is not a ranking)
qwen3.5:9bHANGLIMFORMAT
Show code
```html
<!DOCTYPE html>
<html>
<head>
<title>Binary Search Animation</title>
<style>body { background: #111; display: flex; justify-content: center; align-items: center; height: 100vh; margin: 0; flex-direction: column; color: white; } canvas { border: 1px solid #333; } .info { margin-top: 20px; font-family: monospace; }</style>
</head>
<body>
<canvas id="canvas" width="800" height="250"></canvas>
<div class="info">Target: <span id="target-display"></span> | Comparisons: <span id="comparisons">0</span></div>

<script>
    const canvas = document.getElementById('canvas');
    const ctx = canvas.getContext('2d');
    const ARRAY_SIZE = 40;
    const BAR_WIDTH = (canvas.width - 30) / ARRAY_SIZE * 0.8;
    const PADDING = 15;

    let array = [];
    let targetValue = 0;
    let low = 0;
    let high = ARRAY_SIZE - 1;
    let comparisons = 0;
    let animationFrameId = null;
    let isSearching = false;

    function generateArray() {
        array = [];
        for (let i = 0; i < ARRAY_SIZE; i++) {
            array.push(Math.floor(Math.random() * 90) + 10); // Values between 10 and 100
        }
        targetValue = array[Math.floor(Math.random() * ARRAY_SIZE)];
    }

    function drawArrayState(discardedLow, discardedHigh) {
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        const barSpacing = (canvas.width - PADDING * 2) / Array.from({length: ARRAY_SIZE}, () => 1).length;

        // Draw bars and highlight discarded segments
        for (let i = 0; i < ARRAY_SIZE; i++) {
            let x = PADDING + barSpacing * i + BAR_WIDTH * (i % 2 === 0 ? -0.4 : 0.4);
            let y = 0;
            let height = array[i] * 1.5;

            // Check if the index is in the discarded range [discardedLow, discardedHigh]
            if (i >= Math.min(low, high) && i <= Math.max(low, high)) {
                if ((i < low || i > high) && i !== Math.floor((low + high) / 2)) {
                     ctx.fillStyle = '#444';
                } else if (i === Math.floor((low + high) / 2)) {
                    ctx.fillStyle = '#FFD700'; // Yellow for middle element
                } else {
                    ctx.fillStyle = '#3b82f6';
                }
            } else {
                 // This simplified block assumes we only highlight the search space [low, high]
                 if (i < low) ctx.fillStyle = '#4a5568'; // Grey out left half
                 else if (i > high) ctx.fillStyle = '#4a5568'; // Grey out right half
                 else ctx.fillStyle = '#3b82f6'; 
            }

            ctx.fillRect(x, canvas.height - height, BAR_WIDTH * (i % 2 === 0 ? 1 : 0.8), height);
        }
    }
    
    function drawMarkers(lowIndex, highIndex, midIndex) {
         // Draw low marker
        ctx.beginPath();
        ctx.fillStyle = '#dc2626'; // Red
        ctx.fillRect(PADDING + (canvas.width - PADDING * 2) / ARRAY_SIZE * lowIndex, canvas.height - 10, 8, 10);

        // Draw high marker
        ctx.beginPath();
        ctx.fillStyle = '#dc2626'; // Red
        ctx.fillRect(PADDING + (canvas.width - PADDING * 2) / ARRAY_SIZE * highIndex, canvas.height - 10, 8, 10);

        // Draw middle marker
        ctx.beginPath();
        ctx.fillStyle = '#f59e0b'; // Amber/Yellow
        ctx.fillRect(PADDING + (canvas.width - PADDING * 2) / ARRAY_SIZE * midIndex, canvas.height - 10, 8, 10);
    }

    function updateDisplay() {
        document.getElementById('target-display').textContent = targetValue;
        document.getElementById('comparisons').textContent = comparisons;
    }
    
    function animateSearch(l, h) {
        if (!isSearching) return;

        const mid = Math.floor((l + h) / 2);
        const currentL = low;
        const currentH = high;
        
        drawArrayState(currentL, currentH);
        drawMarkers(currentL, currentH, mid);

        // Search logic visualization: Compare and update state
        comparisons++;
        if (array[mid] === targetValue) {
            isSearching = false;
            alert(`Found target ${targetValue} at index ${mid}! Total comparisons: ${comparisons}`);
            generateArray(); // Restart on success
            animateSearch(0, ARRAY_SIZE - 1);
        } else if (array[mid] < targetValue) {
            low = mid + 1;
            if (low > high) {
                isSearching = false;
                alert(`Target ${targetValue} not found. Total comparisons: ${comparisons}`);
                generateArray(); // Restart on failure
                animateSearch(0, ARRAY_SIZE - 1);
            }
        } else {
            high = mid - 1;
        }

        updateDisplay();

        if (low <= high) {
            animationFrameId = requestAnimationFrame(() => animateSearch(low, high));
        } else {
             isSearching = false;
             // Final cleanup and restart attempt after a delay
             setTimeout(() => {
                alert(`Target ${targetValue} not found. Total comparisons: ${comparisons}`);
                generateArray(); 
                animateSearch(0, ARRAY_SIZE - 1);
            }, 500);
        }
    }

    function startAnimation() {
        if (animationFrameId) cancelAnimationFrame(animationFrameId);
        
        // Reset state and generate new data
        low = 0;
        high = ARRAY_SIZE - 1;
        comparisons = 0;
        isSearching = true;

        generateArray();
        updateDisplay();
        animateSearch(low, high);
    }
    
    // Start the animation immediately upon loading
    startAnimation();

</script>
</body>
</html>
```
qwen3-coder:30bHANGLIMFORMAT
Show code
```html
<!DOCTYPE html>
<html>
<head>
<title>Binary Search Animation</title>
<style>
body { background: #f0f0f0; display: flex; justify-content: center; padding: 20px; }
canvas { border: 1px solid #ccc; background: white; }
#info { margin-left: 30px; font-family: monospace; }
</style>
</head>
<body>
<canvas id="searchCanvas" width="800" height="250"></canvas>
<div id="info">Target: N/A<br>Comparisons: 0</div>

<script>
const canvas = document.getElementById('searchCanvas');
const ctx = canvas.getContext('2d');
const infoDiv = document.getElementById('info');

let arr = [];
let target = 0;
let low = 0;
let high = 39;
let comparisons = 0;
let isSearching = false;
let animationFrameId = null;

function generateArray() {
    arr = Array.from({ length: 40 }, () => Math.floor(Math.random() * 100) + 5);
    arr.sort((a, b) => a - b);
}

function setup() {
    generateArray();
    target = arr[Math.floor(Math.random() * 40)];
    low = 0;
    high = 39;
    comparisons = 0;
    isSearching = true;
    document.getElementById('info').innerHTML = `Target: ${target}<br>Comparisons: 0`;
}

function draw() {
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    const barWidth = (canvas.width - 20) / 40;
    const padding = 10;

    for (let i = 0; i < 40; i++) {
        ctx.fillStyle = 'skyblue';
        ctx.fillRect(padding + i * barWidth, 0, barWidth - 2, arr[i]);
    }

    // Low marker
    ctx.strokeStyle = 'red';
    ctx.lineWidth = 3;
    ctx.beginPath();
    ctx.moveTo(padding + low * (barWidth), canvas.height);
    ctx.lineTo(padding + low * (barWidth), 0);
    ctx.stroke();

    // High marker
    ctx.strokeStyle = 'red';
    ctx.lineWidth = 3;
    ctx.beginPath();
    ctx.moveTo(padding + high * (barWidth) + barWidth - 2, canvas.height);
    ctx.lineTo(padding + high * (barWidth) + barWidth - 2, 0);
    ctx.stroke();

    // Middle marker (Highlight)
    if (!isNaN(mid)) {
        const midX = padding + mid * barWidth;
        ctx.fillStyle = 'rgba(255, 165, 0, 0.7)'; // Orange highlight
        ctx.fillRect(midX, 0, barWidth - 2, canvas.height);

    } else { // Draw discarded segment (Grey)
        if (low > 0 && low < high) {
            const startX = padding + Math.min(low, mid_old) * barWidth;
            const endX = padding + Math.max(low, mid_old) * barWidth + (barWidth - 2);
            ctx.fillStyle = 'rgba(180, 180, 180, 0.5)'; // Grey overlay
            ctx.fillRect(startX, 0, endX - startX, canvas.height);
        }
    }

    // Update Info Display
    infoDiv.innerHTML = `Target: ${target}<br>Comparisons: ${comparisons}`;
}

let mid_old = null;

function step() {
    if (!isSearching) return;

    mid = Math.floor((low + high) / 2);
    const comparisonResult = arr[mid] < target ? 1 : (arr[mid] > target ? -1 : 0);

    draw(); // Draw before state change, showing the element being compared

    setTimeout(() => {
        if (comparisonResult === 0) {
            isSearching = false;
            alert(`Found ${target} at index ${mid}!`);
            setup(); // Restart animation
            return;
        } else if (comparisonResult > 0) {
            low = mid + 1;
        } else {
            high = mid - 1;
        }

        comparisons++;
        mid_old = mid; // Record previous position for grey highlight on next draw
        draw(); // Draw after state change (new low/high)

        if (low > high) {
            isSearching = false;
            alert(`Target ${target} not found.`);
            setup(); // Restart animation
        } else {
            animationFrameId = requestAnimationFrame(step);
        }
    }, 500);
}

let mid = null;

function animate() {
    if (!isSearching) return;
    requestAnimationFrame(step);
}

// Start the process
setup();
animate();
</script>
</body>
</html>
```
qwen3:8bharness
No answer reached us (ERR) — and the reason lies with our setup, not with the model: reasoning consumed the entire token budget and the answer stayed empty; the gateway rejects budgets above 3000 tokens Counted as a did-not-finish, but it is not evidence about this model.
mistral-small:24bOKFORMAT
Show code
```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Binary Search Animation</title>
<style>
  body { font-family: Arial, sans-serif; }
  #canvas { border: 1px solid black; }
</style>
</head>
<body>

<canvas id="canvas" width="800" height="400"></canvas>
<div id="info"></div>

<script>
// Initialize canvas and context
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');

let array = Array.from({ length: 40 }, (_, i) => i + 1);
array.sort(() => Math.random() - 0.5);

let target = array[Math.floor(Math.random() * 40)];
let low = 0;
let high = array.length - 1;
let comparisons = 0;

function drawArray(arr, low, high, mid) {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  const barWidth = canvas.width / arr.length;
  for (let i = 0; i < arr.length; i++) {
    let color = 'grey';
    if (i === mid) color = 'red';
    else if (i >= low && i <= high) color = 'blue';

    ctx.fillStyle = color;
    ctx.fillRect(i * barWidth, canvas.height - arr[i] * 10, barWidth, arr[i] * 10);
    ctx.fillStyle = 'black';
    ctx.fillText(arr[i], i * barWidth + 2, canvas.height - arr[i] * 10 - 5);
  }
}

function animateBinarySearch() {
  if (low > high) return;

  let mid = Math.floor((low + high) / 2);

  drawArray(array, low, high, mid);
  comparisons++;
  document.getElementById('info').innerText = `Target: ${target}, Comparisons: ${comparisons}`;

  requestAnimationFrame(() => {
    if (array[mid] === target) {
      setTimeout(() => animateBinarySearch(), 500);
    } else if (array[mid] < target) {
      low = mid + 1;
      array.fill('grey', 0, mid);
      setTimeout(() => animateBinarySearch(), 500);
    } else {
      high = mid - 1;
      array.fill('grey', mid + 1, high + 1);
      setTimeout(() => animateBinarySearch(), 500);
    }
  });
}

animateBinarySearch();
</script>

</body>
</html>
```
deepseek-r1:14bERRBLANKMINIFIED
Show code
<!DOCTYPE html>
<html><head><style>canvas{border:1px solid #ccc}.labels{text-align:center;position:absolute;top:20px;left:50%;transform:translateX(-50%)}#t,#c{color:#fff;background:black;padding:5px 10px;position:absolute;bottom:10px;width:200px}</style></head><body><canvas id="cvs"></canvas><div class="labels" id="lbls"></div><div id="t">Target: </div><div id="c">Comparisons: 0</div><script>let cvas=document.getElementById('cvs'), ctx=cvas.getContext('2d'), w=1000,h=600, maxVal=40,a=[...Array(40)].map((_,i)=>i+1).sort();a.sort(()=>Math.random()-0.5);let target=a[Math.floor(Math.random()*a.length)], comparisons=0,cvsLen=40,len=w/40;function drawBar(x,y,h,w=2){ctx.fillStyle='#bbb';ctx.fillRect(x,y,w,h)}function drawBars(){cvas.width=h;lbls.innerHTML='';for(let i=0;i<40;i++){const x=i*len, val=a[i];const label=document.createElement('div');label.style.position='absolute';label.style.left=x+'px';label.style.top='15px';label.textContent=i+1;document.getElementById('lbls').appendChild(label);drawBar(x,h-val*4,maxVal/2*4)}}function mid(a,b){return Math.floor((a+b)/2}function binarySearchStep(l,r){if(l>=(r)) return;const m=mid(l,r), mL=m-1, mR=m+1;if(m === targetIndex) comparisons++;ctx.fillStyle='#f00';ctx.fillRect(len*m, h-val*4,2,val[m]*4);requestAnimationFrame(_=>{binarySearchStep(l,m);binarySearchStep(m+1,r)})}let targetIndex=a.indexOf(target), steps=0;drawBars();function animate(){let low=0,high=39;steps++;if(steps>Math.log2(40))return;ctx.fillStyle='#ccc';if(high >=low){const midPoint=mid(low,high);if(a[midPoint]==target) comparisons++;else if(a[midPoint]<target) low=midPoint+1 else high=midPoint-1;if(midPoint==mid(low,mid(low,high))){binarySearchStep(low,high)}}requestAnimationFrame(animate)}window.onload=animate;</script></body></html>
qwen3:14bOKLIMFORMAT
Show code
```html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Animated Binary Search</title>
    <style>
        body { background: #1e1e2e; color: white; font-family: monospace; display: flex; flex-direction: column; align-items: center; padding: 20px; }
        #canvas { border: 1px solid #444; background: #27293d; }
        .info { margin-top: 15px; font-size: 1.1em; }
    </style>
</head>
<body>
    <h1>Binary Search Simulation (N=40)</h1>
    <canvas id="canvas" width="800" height="300"></canvas>

    <div class="info">
        Target Value: <span id="target-val"></span> | Comparisons: <span id="comp-count">0</span>
        <p>(Greyed area is discarded)</p>
    </div>

    <script>
        const canvas = document.getElementById('canvas');
        const ctx = canvas.getContext('2d');
        const N = 40;
        let array = [];
        let target = 0;
        let low, high;
        let comparisons = 0;
        
        // State machine for animation
        let state = 'INIT'; // INIT -> RUNNING_STEP -> RESULT
        let currentStep = 0;
        const MAX_STEPS = 15;

        function init() {
            array = Array.from({ length: N }, () => Math.floor(Math.random() * 90) + 10);
            // Ensure target exists and is within the array range
            target = array[Math.floor(Math.random() * N)];

            low = 0;
            high = N - 1;
            comparisons = 0;
            currentStep = 0;
            state = 'INIT';

            document.getElementById('target-val').textContent = target;
            document.getElementById('comp-count').textContent = comparisons;
        }

        function draw() {
            ctx.clearRect(0, 0, canvas.width, canvas.height);
            const barWidth = (canvas.width / N) * 0.8;
            const padding = (canvas.width / N) * 0.2;

            // 1. Draw Bars and Labels
            for (let i = 0; i < N; i++) {
                ctx.fillStyle = '#6a7b9c'; // Default bar color
                ctx.fillRect(i * (barWidth + padding) + padding, 20, barWidth, array[i] * 10);
                ctx.fillStyle = 'white';
                ctx.font = '10px monospace';
                ctx.fillText(array[i], i * (barWidth + padding) + padding - 5, 15);
            }

            // 2. Highlight Discarded Area (Previous step's discard)
            if (state === 'RUNNING_STEP' && currentStep > 0) {
                let start = Math.max(0, low);
                let end = Math.min(N - 1, high);

                // If we are in the middle of a comparison cycle and have established bounds:
                if (start < N && end >= 0) {
                    ctx.fillStyle = 'rgba(105, 105, 105, 0.3)'; // Grey highlight
                    const xStart = start * (barWidth + padding) + padding;
                    const width = Math.min(N, Math.max(0, end - start + 1)) * (barWidth + padding);
                    ctx.fillRect(xStart, 0, width, canvas.height);
                }
            }

            // 3. Draw Low/High/Mid Markers
            let currentLow = low;
            let currentHigh = high;
            let mid = Math.floor((currentLow + currentHigh) / 2);

            if (currentLow >= 0 && currentLow < N) {
                ctx.strokeStyle = '#ff5555'; // Low marker color
                ctx.lineWidth = 3;
                ctx.beginPath();
                ctx.moveTo(currentLow * (barWidth + padding) + padding - 10, 0);
                ctx.lineTo(currentLow * (barWidth + padding) + padding - 10, canvas.height);
                ctx.stroke();
            }

            if (currentHigh >= 0 && currentHigh < N) {
                ctx.strokeStyle = '#55aaff'; // High marker color
                ctx.lineWidth = 3;
                ctx.beginPath();
                ctx.moveTo(currentHigh * (barWidth + padding) + padding - 10, 0);
                ctx.lineTo(currentHigh * (barWidth + padding) + padding - 10, canvas.height);
                ctx.stroke();
            }

            // 4. Highlight Middle Element being compared
            if (mid >= 0 && mid < N) {
                ctx.fillStyle = 'rgba(255, 200, 0, 0.7)'; // Yellow highlight
                const x = mid * (barWidth + padding) + padding;
                ctx.fillRect(x - 15, 0, barWidth + 30, canvas.height);

                // Draw 'Mid' label
                ctx.fillStyle = '#ffcc00';
                ctx.font = 'bold 14px monospace';
                ctx.fillText('MID', x, 25);
            }

             // 5. Target Marker (Conceptual display)
            ctx.strokeStyle = '#8aff8a'; // Green outline for target spot
            ctx.lineWidth = 2;
            const targetX = (array.indexOf(target) * (barWidth + padding)) + padding - 10;

            // Instead of drawing a line, just draw the bar itself with a subtle green border
            if (array.indexOf(target) !== -1) {
                 ctx.strokeStyle = '#8aff8a';
                 ctx.lineWidth = 5;
                 ctx.strokeRect(array.indexOf(target) * (barWidth + padding) + padding - 2, 0, barWidth + 4, canvas.height);
            }
        }

        function stepSearch() {
            if (low > high || state === 'RESULT') {
                state = 'FINISHED';
                draw();
                return;
            }

            const mid = Math.floor((low + high) / 2);
            comparisons++;
            document.getElementById('comp-count').textContent = comparisons;

            if (array[mid] === target) {
                state = 'SUCCESS';
                draw();
                return;
            } else if (array[mid] < target) {
                low = mid + 1;
            } else {
                high = mid - 1;
            }

            // Check for failure condition after update
            if (low > high) {
                 state = 'FAILURE';
            }
        }

        function animate() {
            if (state === 'INIT' || state === 'RUNNING_STEP') {
                draw();
                stepSearch();
                // Only step and redraw if the search is still active or hasn't completed its steps
                if (state !== 'FINISHED' && state !== 'SUCCESS' && state !== 'FAILURE') {
                    setTimeout(() => requestAnimationFrame(animate), 500); // Wait half a second per comparison
                } else {
                     // If it reached the final state, stop recursion. The final draw() happens in stepSearch().
                    return;
                }

            } else if (state === 'FINISHED' || state === 'SUCCESS' || state === 'FAILURE') {
                clearInterval(window.animationInterval);
                const result = state === 'SUCCESS' ? "Found!" : 
                              state === 'FAILURE' ? "Not found." : "";
                alert(`Search Finished! ${result} Comparisons used: ${comparisons}`);

                // Restart the process after a delay
                setTimeout(() => {
                    init();
                    requestAnimationFrame(animate);
                }, 2000);
            }
        }

        // Initialization and Start
        init();
        window.animationInterval = requestAnimationFrame(animate);

    </script>
</body>
</html>
```
gemma4:26bharness
No answer reached us (THIN) — and the reason lies with our setup, not with the model: reasoning consumed the entire token budget (3 min 28 s, zero characters of answer); larger budgets are refused by the gateway Counted as a did-not-finish, but it is not evidence about this model.
llama3.1:8bSTATFORMAT
Show code
```html
<!DOCTYPE html>
<html>
<head>
  <title>Binary Search Animation</title>
  <style>
    /* add some basic styling */
    body {
      background-color: #f0f0f0;
    }
    canvas {
      border: 1px solid black;
    }
  </style>
</head>
<body>
<canvas id="canvas" width="600" height="400"></canvas>

<script>
  var ctx = document.getElementById('canvas').getContext('2d');
  var array = Array.from({length:40}, (_, i) => Math.random() * (100 - 1) + 1);
  array.sort((a, b) => a-b);

  function draw(arr) {
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    ctx.fillStyle = 'black';
    for(let i = 0; i < arr.length; i++) {
      const x = (canvas.width / arr.length) * i;
      ctx.fillRect(x, canvas.height - (arr[i] + 1), canvas.width/arr.length, 2);
      ctx.fillStyle = 'black';
      ctx.font = "12px Arial";
      ctx.textAlign = "center";
      ctx.textBaseline = "top";
      ctx.fillText(i, x + (canvas.width / arr.length) / 2, canvas.height - (arr[i] + 1));
    }
    ctx.beginPath();
    ctx.lineWidth = 3;
    ctx.moveTo(0, canvas.height);
    for(let i = 0; i < arr.length; i++) {
      const x = (canvas.width / arr.length) * i;
      ctx.lineTo(x, canvas.height - 2);
      if(i === low && i <= high) ctx.fillStyle = 'red';
      else if(i >= low && i > high) ctx.fillStyle = 'grey';
      else ctx.fillStyle = 'black';
    }
    ctx.stroke();
    ctx.fillStyle = 'black';
    ctx.font = "24px Arial";
    ctx.textAlign = "left";
    ctx.textBaseline = "top";
    ctx.fillText(`Target: ${target}`, 20, 20);
    ctx.font = "18px Arial";
    ctx.fillText(`Comparsions: ${comparsions}`, 20, 50);
  }

  var low = 0;
  var high = array.length - 1;
  var target = Math.floor(Math.random() * (array[array.length-1] + 1));
  var comparsions = 0;

  function animate() {
    requestAnimationFrame(animate);
    const mid = Math.floor((low+high)/2);
    ctx.fillStyle = 'black';
    ctx.font = "24px Arial";
    ctx.textAlign = "left";
    ctx.textBaseline = "top";
    ctx.fillText(`Target: ${target}`, 20, 20);
    if(mid === high || mid < low) {
      draw(array);
      comparsions++;
      setTimeout(() => {location.reload()}, 2000);
      return;
    }
    const middleValue = array[mid];
    ctx.fillStyle = 'yellow';
    const x = (canvas.width / array.length) * mid;
    ctx.fillRect(x, canvas.height - (middleValue + 1), canvas.width/array.length, 2);
    ctx.fillStyle = 'black';
    ctx.font = "12px Arial";
    ctx.textAlign = "center";
    ctx.textBaseline = "top";
    ctx.fillText(mid, x + (canvas.width / array.length) / 2, canvas.height - (middleValue + 1));

    if(target < middleValue) {
      high = mid;
      comparsions++;
    } else {
      low = mid + 1;
      comparsions++;
    }
    draw(array);
  }

  animate();
</script>
</body>
</html>
```
command-r:35bOKLIM
Show code
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Binary Search Visualization</title>
    <style>
        body {
            margin: 0;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            background-color: #f4f4f4;
        }

        canvas {
            border: 2px solid #333;
            box-shadow: 2px 2px 10px rgba(0, 0, 0, 0.1);
        }
    </style>
</head>
<body>

    <canvas id="myCanvas" width="800" height="400"></canvas>

    <script>

        const canvas = document.getElementById('myCanvas');
        const ctx = canvas.getContext('2d');
        
        function randomizeArray(min, max) {
            return Array.from({ length: 40 }, () => Math.floor(Math.random() * (max - min + 1)) + min);
        }

        let array = randomizeArray(-50, 50);
        let targetValue;
        
        function drawBars() {
            ctx.clearRect(0, 0, canvas.width, canvas.height);

            const barWidth = canvas.width / array.length;
            let x = 0;
    
            for (let i = 0; i < array.length; i++) {
                if (!targetValue || Math.abs(array[i] - targetValue) > Math.abs(array[Math.floor(array.length/2)] - targetValue)) {
                    ctx.fillStyle = '#f4f4f4';
                } else {
                    ctx.fillStyle = i === array.length/2 ? 'yellow' : '#ccc';
                }
                ctx.fillRect(x, canvas.height * 0.65, barWidth, canvas.height * 0.35);
                ctx.fillStyle = '#333';
                ctx.fillText(array[i], x + barWidth/2, canvas.height - (canvas.height * 0.1));
                
                if (targetValue === array[i]) {
                    ctx.strokeRect(x, canvas.height * 0.65, barWidth, canvas.height * 0.35);
                }
    
                x += barWidth;
            }
        }
        
        function drawLowHigh() {
            const lowX = (array.indexOf(targetValue) + 1) * canvas.width / array.length;
            ctx.strokeStyle = 'green';
            ctx.beginPath();
            ctx.moveTo(lowX, 0);
            ctx.lineTo(lowX, canvas.height);
            ctx.stroke();

            const highX = (array.indexOf(targetValue) - 1 + array.length) * canvas.width / array.length;
            ctx.strokeStyle = 'red';
            ctx.beginPath();
            ctx.moveTo(highX, 0);
            ctx.lineTo(highX, canvas.height);
            ctx.stroke();
        }

        function drawMiddle() {
            const middleIndex = Math.floor((array.length - 1) / 2);
            const middleBarWidth = canvas.width / array.length;
            const middleX = (middleIndex + 0.5) * middleBarWidth;

            ctx.strokeStyle = 'green';
            ctx.beginPath();
            ctx.moveTo(middleX, 0);
            ctx.lineTo(middleX, canvas.height);
            ctx.stroke();
        }

        function binarySearch() {
            
            array = randomizeArray(-50, 50).sort((a, b) => a - b);

            drawBars();
            targetValue = array[Math.floor(array.length/2)];

            let left = 0;
            let right = array.length - 1;
            let count = 0;
            
            function animate() {
                requestAnimationFrame(animate);

                if (right >= left) {
                    const middleIndex = Math.floor((left + right)/2);
                    drawMiddle(); // Draw the Middle Marker
    
                    if (array[middleIndex] === targetValue) {
                        ctx.fillStyle = 'green';
                        ctx.font = "bold 16px Arial";
                        ctx.fillText('Target Found!', canvas.width / 4, canvas.height - 20);
                        count++;
                        return; // No need to continue search
                    } else if (array[middleIndex] > targetValue) {
                        right = middleIndex - 1;
                    } else {
                        left = middleIndex + 1;
                    }
    
                    drawLowHigh();
                } else {
                    ctx.fillStyle = 'green';
                    ctx.font = "bold 16px Arial";
                    ctx.fillText('Target Not Found!', canvas.width / 4, canvas.height - 20);
                    count++;
                    return; // Search complete
                }
    
                const targetValueText = `Target: ${targetValue}`;
                const comparisonsText = `Comparisons: ${count}`;
                
                ctx.font = "16px Arial";
                ctx.fillStyle = '#333';
                ctx.fillText(targetValueText, canvas.width / 2 - ctx.measureText(targetValueText).width / 2, 50);
                ctx.fillText(comparisonsText, canvas.width / 2 - ctx.measureText(comparisonsText).width / 2, 75);
            }

            animate();
        }

        binarySearch();

    </script>
</body>
</html>
qwq:32bSTAT
Show code
<think>

Okay, I need to create an HTML file that animates a binary search on a sorted array of 40 values. The user wants it to be self-contained, under 120 lines, and uses requestAnimationFrame for smooth animation. Let me think through how to approach this.

First, the HTML structure: I'll need a canvas element and maybe some divs to display the target value and comparisons count. But since the user specifies to output only the HTML content, I should include all elements within the HTML file.

The canvas will draw the bars. Each bar's height corresponds to its value. The array needs to be sorted, so I'll generate random numbers and sort them. The target is a random element from the array to ensure it's found.

For the binary search animation, I'll need to track low, high, and mid indices. The middle element should be highlighted, and the region that's discarded (either left or right) should be greyed out. The animation should update the canvas each frame, showing these markers as they change steps.

I'll need a state object to track the current step, the array, target, comparisons, etc. The animation loop will handle the steps. When the search completes, it should restart with a new random array and target.

Using requestAnimationFrame, I can control the animation speed by only progressing the step after a certain time has passed. Maybe a flag to indicate when to proceed.

Let me outline the steps:

1. Setup: Generate the sorted array, set the target, initialize low and high, and reset counters.
2. Draw function: Redraw the canvas each frame, showing bars, markers for low/high/mid, highlight the middle bar, and shade the discarded half.
3. The animation loop: Check if the search is ongoing. If mid is found, proceed until low > high. Update step variables accordingly and increment comparisons.
4. When done, restart by generating a new array and resetting variables.

Implementing the binary search logic step by step is crucial. Each frame should check if it's time to proceed to the next step. Using timeouts or a timer within the animation loop might be tricky. Alternatively, track the time elapsed and only progress when a certain interval has passed.

Wait, using requestAnimationFrame's timestamp can help. Let me think: each frame checks whether enough time has passed since the last step. If so, compute the next step's variables and then redraw. So, the state will have a lastStepTime variable, and when the delta is sufficient, we move to the next step.

Also, the drawing part: the bars are drawn with rectangles. The middle bar is highlighted (maybe red), the current low and high can have markers like lines. The discarded half (either left or right of mid) can be drawn in a lighter color.

Let me plan the variables:

- array: sorted array of 40 elements.
- target: a random element from the array.
- low, high, mid: indices for the search.
- comparisons: increments each comparison.
- done: flag to know when to restart.
- step: to track the animation phase (maybe not needed if handled via time).
- animating: boolean to control loop.

The initial setup: generate the array. Let's say each number between 1 and 40, but shuffled then sorted? Wait, no. Wait, the array should be sorted, with unique values. Maybe generate 40 unique random numbers, sort them, then pick a random element as target.

Wait, the array needs to be sorted. So generate 40 unique numbers, sort them, then target is one of them.

Wait, but maybe for simplicity, numbers can be 1 to 40, sorted. That would be easier. Wait, but the problem says "sorted array of 40 values". So generating 40 sorted numbers, but can be any values as long as sorted. To make it look better, maybe random values between 1 and a max, sorted.

Alternatively, just use numbers 1 to 40 in order. That might be too predictable, but okay.

Hmm, the target can be a random element from the array. Let's say:

array = Array.from({length:40}, (_,i)=>i+1).sort((a,b)=>a-b); // sorted.

Wait, but that's just 1-40 in order. Maybe better to generate random numbers and sort them. Let's do that:

function generateArray() {
  return Array.from({length:40}, () => Math.floor(Math.random() * 200) + 1).sort((a,b)=>a-b);
}

Yes. Then the target is array[Math.floor(Math.random() * 40)].

Next, the canvas drawing. The canvas needs to be sized appropriately. Let's set width and height in the HTML element, say 800x400.

The bars: each bar's width is canvas.width / array.length, so 800 /40 =20px per bar. The height is scaled to fit the canvas height minus some margin. The maximum value in the array will determine the scaling factor.

The drawing steps:

- Clear the canvas.
- Draw all bars: for each element, the x is i*barWidth, the height is (value/maxValue)*canvasHeight (minus some padding).
- The middle element is highlighted (red), low and high are marked with lines or markers.
- The region to grey out: for example, if searching left, the right half (from mid+1 to high) is greyed. Or the other way around.

Wait, the discarded half is either left (low to mid-1) or right (mid+1 to high). So after comparing, we adjust low or high. So when we do mid = Math.floor((low + high)/2), then if target < array[mid], we set high = mid -1, so the right half is discarded, so the area from mid to high is the one being eliminated.

So, to grey out: if the next step is moving to left (target < array[mid]), then the region from mid to high is shaded. Or moving right, shade low to mid.

Hmm, need to track which half was discarded in each step. Maybe store the previous low/high and mid to determine which half to shade.

Alternatively, during each step:

After computing mid, the comparison is done. Depending on whether target is less than or greater than array[mid], the next step adjusts high or low, so the opposite half is kept.

Wait, in binary search:

if (array[mid] < target) low = mid +1; // discard left, keep right (mid+1 to high)

else high = mid -1; // discard right (mid to high), keep left (low to mid)

So the discarded portion is either left (before mid) if we went to the right, or right (after mid) if we went left.

Wait, not exactly. Let's see:

Suppose target is greater than array[mid]. Then next step's low becomes mid +1, so the new low is higher. So the left half up to mid is discarded.

Similarly, if target is less than array[mid], then high becomes mid-1, so the right half from mid onwards is discarded.

So, in the current step, after mid is calculated and compared, the region that is discarded is either the left half or right half. The discarded region can be the one that's being eliminated. So when the next step happens, that region should be shaded grey.

Therefore, in each step's animation, after the comparison, we can determine which half is being discarded and shade it.

But in terms of code, during the animation loop,
deepseek-r1:32bBLANKLIMFORMAT
Show code
```html
<!DOCTYPE html>
<html><head><style>body{margin:0;display:flex;flex-direction:column;justify-content:center;height:100vh;background:#1a1a1a;color:white;font-family:sans-serif}.canvas-container{width:800px;margin:20px auto}.bars canvas{border:1px solid #333}.info{text-align:center;padding:10px}</style></head>
<body><div class="canvas-container"><div class="info">Target: <span id="target"></span> | Comparisons: <span id="comps"></span></div><div class="bars"><canvas width="800" height="400" id="barsCanvas"></canvas></div></div>
<script>
class BinarySearchVisualizer {
  constructor() {
    this.canvas = document.getElementById('barsCanvas');
    this.ctx = this.canvas.getContext('2d');
    this.array = [];
    this.low = -1;
    this.high = -1;
    this.middle = -1;
    this.target = -1;
    this.comparisons = 0;
    this.animationId = null;
    this.initialize();
  }

  generateArray() {
    const min = 50;
    const max = 250;
    const size = 40;
    let arr = [];
    for (let i=0; i<size; i++) {
      arr.push(Math.floor(Math.random()*(max-min+1)+min));
    }
    return arr.sort((a,b)=>a-b);
  }

  drawBars() {
    this.ctx.clearRect(0,0,this.canvas.width,this.canvas.height);
    
    const barWidth = (this.canvas.width - 60)/this.array.length;
    let x = 30;

    for(let i=0; i<this.array.length; i++) {
      const height = this.array[i];
      const color = '#2196F3';
      if(i === this.middle) {
        this.ctx.fillStyle = '#4CAF50';
      } else if(i >= this.low && i <= this.high) {
        this.ctx.fillStyle = (i===this.low || i===this.high) ? '#FF5722' : '#2196F3';
      } else if(i < this.low || i > this.high) {
        this.ctx.fillStyle = '#808080';
      }
      
      this.ctx.fillRect(x, this.canvas.height - height, barWidth-2, height);
      x += barWidth;
    }

    for(let i=0; i<this.array.length; i++) {
      const x = 30 + i*(barWidth) + (barWidth/2);
      const y = this.canvas.height - this.array[i] - 5;
      this.ctx.fillStyle = '#fff';
      this.ctx.font = '12px Arial';
      this.ctx.fillText(this.array[i],x,y);
    }
  }

  setValues(low, high, middle) {
    this.low = low;
    this.high = high;
    this.middle = middle;
    document.getElementById('target').textContent = this.target;
    document.getElementById('comps').textContent = this.comparisons;
  }

 *//*

function BinarySearchVisualizer() {
  this.array = [];
  this.canvas = document.getElementById('barsCanvas');
  this.ctx = this.canvas.getContext('2d');
  this.reset();
}

BinarySearchVisualizer.prototype.reset = function() {
  const arr = [];
  for(let i=0; i<40; i++) {
    arr.push(Math.floor(Math.random()*300+50));
  }
  this.array = arr.sort((a,b) => a - b);
  this.low = 0;
  this.high = this.array.length-1;
  this.middle = -1;
  this.target = Math.floor(Math.random()*this.array[this.array.length-1]);
  this.comparisons = 0;
  this.draw();
};

BinarySearchVisualizer.prototype.setTarget = function(target) {
  this.target = target;
};

BinarySearchVisualizer.prototype.compareMiddle = function() {
  if(this.middle === -1) return;
  
  const comparison = this.array[this.middle] > this.target ? 'right' : 
                    (this.array[this.middle] < this.target) ? 'left' : 'found';
  
  this.comparisons++;
  
  requestAnimationFrame(() => {
    if(comparison === 'found') {
      alert('Found at index '+this.middle+' with '+this.comparisons+' comparisons!');
      this.reset();
      return;
    }

    if(comparison === 'right') {
      this.low = this.middle +1;
    } else {
      this.high = this.middle -1;
    }
    
    if(this.low > this.high) {
      alert('Not found after '+this.comparisons+' comparisons!');
      this.reset();
      return;
    }
    
    this.middle = Math.floor( (this.low + this.high)/2 );
    this.draw();
  });
};

BinarySearchVisualizer.prototype.draw = function() {
  const barWidth = (800-60)/40;
  let x = 3
Outside the Brain cluster — same task, same character budget, collected through their own tooling (response times not comparable)
GPT-5.5 (Codex)frontier referenceOK
Show code
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Binary Search Canvas</title>
<style>
html,body{margin:0;height:100%;background:#10151d;color:#e9edf3;font-family:system-ui,Segoe UI,sans-serif;overflow:hidden}
canvas{display:block;width:100vw;height:100vh}
</style>
</head>
<body>
<canvas id="c"></canvas>
<script>
const c=document.getElementById("c"),x=c.getContext("2d");
let a,t,lo,hi,mid,cmp,phase,stepT,last,done,discard,found;
function rnd(){
 let s=new Set;while(s.size<40)s.add(5+Math.floor(Math.random()*94));
 a=[...s].sort((p,q)=>p-q);t=a[Math.floor(Math.random()*a.length)];
 if(Math.random()<.35)t=5+Math.floor(Math.random()*94);
 lo=0;hi=39;cmp=0;phase=0;stepT=0;done=false;discard=[];found=-1;mid=Math.floor((lo+hi)/2);
}
function fit(){
 let d=devicePixelRatio||1;c.width=innerWidth*d;c.height=innerHeight*d;x.setTransform(d,0,0,d,0,0);
}
function mark(label,i,col,y){
 let W=innerWidth,p=28,g=3,bw=(W-p*2-g*39)/40,cx=p+i*(bw+g)+bw/2;
 x.fillStyle=col;x.beginPath();x.moveTo(cx,y);x.lineTo(cx-8,y-14);x.lineTo(cx+8,y-14);x.fill();
 x.font="700 13px system-ui";x.textAlign="center";x.fillText(label,cx,y-19);
}
function draw(time){
 if(!last)last=time;let dt=Math.min(40,time-last);last=time;stepT+=dt;
 let W=innerWidth,H=innerHeight,p=28,base=H-82,top=118,g=3,bw=(W-p*2-g*39)/40,max=Math.max(...a);
 x.clearRect(0,0,W,H);
 let fade=Math.min(1,stepT/620),pulse=.5+.5*Math.sin(time/110);
 x.fillStyle="#e9edf3";x.font="700 24px system-ui";x.textAlign="left";
 x.fillText("Binary search",p,42);
 x.font="16px system-ui";x.fillStyle="#b8c2d0";
 x.fillText("target "+t+"   comparisons "+cmp,p,70);
 for(let i=0;i<40;i++){
  let h=(a[i]/max)*(base-top),bx=p+i*(bw+g),by=base-h,dead=discard.some(r=>i>=r[0]&&i<=r[1]);
  let col=dead?"#3b414b":i===mid&&!done?`rgb(${230+25*pulse|0},${130+70*pulse|0},72)`:i===found?"#42d392":i>=lo&&i<=hi?"#4da3ff":"#64748b";
  x.fillStyle=col;x.globalAlpha=dead?.35:1;x.fillRect(bx,by,bw,h);x.globalAlpha=1;
  x.fillStyle=dead?"#7d8795":"#e9edf3";x.font="10px system-ui";x.textAlign="center";
  x.fillText(a[i],bx+bw/2,by-5);
 }
 if(!done){mark("low",lo,"#f1c40f",base+24);mark("mid",mid,"#ff8a3d",base+46);mark("high",hi,"#e85d75",base+24);}
 else{
  x.fillStyle=found>-1?"#42d392":"#e85d75";x.font="700 24px system-ui";x.textAlign="center";
  x.fillText(found>-1?"found at index "+found:"not found",W/2,H-28);
 }
 if(stepT>900&&!done){
  cmp++;
  if(a[mid]===t){found=mid;done=true;stepT=0}
  else if(a[mid]<t){discard.push([lo,mid]);lo=mid+1}
  else{discard.push([mid,hi]);hi=mid-1}
  if(!done&&lo<=hi)mid=Math.floor((lo+hi)/2);else if(!done){done=true;stepT=0}
 }
 if(done&&stepT>1500)rnd();
 requestAnimationFrame(draw);
}
addEventListener("resize",fit);fit();rnd();requestAnimationFrame(draw);
</script>
</body>
</html>
Claude Sonnet 5frontier referenceOK
Show code
<!DOCTYPE html><html><head><meta charset="utf8"><title>Binary Search</title><style>
body{margin:0;background:#111;color:#eee;font-family:monospace}canvas{display:block;margin:20px auto;background:#181818}
</style></head><body>
<canvas id="c" width="900" height="480"></canvas>
<script>
const cv=document.getElementById('c'),cx=cv.getContext('2d');
const N=40,barW=20,gap=2,ox=20,oy=380;
let arr,target,lo,hi,mid,discarded,comparisons,found,phase,pause,frame;
function reset(){
 arr=[];let v=Math.floor(Math.random()*5);
 for(let i=0;i<N;i++){v+=1+Math.floor(Math.random()*5);arr.push(v)}
 target=arr[Math.floor(Math.random()*N)];
 if(Math.random()<0.15)target=-99;
 lo=0;hi=N-1;mid=Math.floor((lo+hi)/2);discarded=new Array(N).fill(false);
 comparisons=0;found=-1;phase='step';pause=0;frame=0
}
function step(){
 if(lo>hi){phase='done';pause=110;return}
 mid=Math.floor((lo+hi)/2);
 comparisons++;
 if(arr[mid]===target){found=mid;phase='done';pause=110;return}
 if(arr[mid]<target){for(let i=lo;i<=mid;i++)discarded[i]=true;lo=mid+1}
 else{for(let i=mid;i<=hi;i++)discarded[i]=true;hi=mid-1}
}
function draw(){
 cx.fillStyle='#181818';cx.fillRect(0,0,cv.width,cv.height);
 let maxV=Math.max(...arr);
 for(let i=0;i<N;i++){
  let x=ox+i*(barW+gap);
  let hgt=10+(arr[i]/maxV)*300;
  let y=oy-hgt;
  let col='#39c';
  if(discarded[i])col='#333';
  if(i===lo&&!discarded[i]&&phase==='step')col='#8f8';
  if(i===hi&&!discarded[i]&&phase==='step')col='#f88';
  if(i===mid&&phase==='step')col='#ff0';
  if(found===i)col='#0f0';
  cx.fillStyle=col;
  cx.fillRect(x,y,barW,hgt);
  cx.fillStyle=discarded[i]?'#666':'#fff';
  cx.font='10px monospace';cx.textAlign='center';
  cx.fillText(arr[i],x+barW/2,y-4);
  cx.fillText(i,x+barW/2,oy+14)
 }
 if(phase==='step'){
  let xl=ox+lo*(barW+gap)+barW/2,xh=ox+hi*(barW+gap)+barW/2,xm=ox+mid*(barW+gap)+barW/2;
  cx.fillStyle='#8f8';cx.fillText('LOW',xl,oy+28);
  cx.fillStyle='#f88';cx.fillText('HIGH',xh,oy+28);
  cx.fillStyle='#ff0';cx.fillText('MID',xm,oy+42)
 }
 cx.fillStyle='#fff';cx.font='18px monospace';cx.textAlign='left';
 cx.fillText('Target: '+target+'   Comparisons: '+comparisons,20,25);
 if(phase==='done'){
  cx.fillStyle=found>=0?'#4f4':'#f66';
  cx.fillText(found>=0?('FOUND at index '+found):'NOT FOUND',20,50)
 } else {
  cx.fillText('Comparing arr['+mid+']='+arr[mid]+' to target '+target,20,50)
 }
}
function loop(){
 frame++;
 if(phase==='step'){if(frame%40===0)step()}
 else if(phase==='done'){pause--;if(pause<=0)reset()}
 draw();
 requestAnimationFrame(loop)
}
reset();loop();
</script></body></html>
Claude Haiku 4.5frontier referenceOK
Show code
<!DOCTYPE html><html><head><title>r70</title></head><body><canvas id="c"></canvas><script>
let c=document.getElementById('c'),x=c.getContext('2d');c.width=800;c.height=600;
let n=40,arr=Array(n).fill(0).map((v,i)=>i*25+Math.floor(Math.random()*5));
let lo=0,hi=n-1,mid=(lo+hi)>>1,cmp=0,done=false,tgt=arr[Math.floor(Math.random()*n)],t=0;
function draw(){
  x.fillStyle="#fff";x.fillRect(0,0,800,600);
  let w=Math.floor(750/n);
  // Draw bars
  x.fillStyle="#000";x.font="10px mono";
  for(let i=0;i<n;i++){
    let h=(arr[i]/1000)*300;
    if(i<lo||i>hi)x.fillStyle="#ccc";else if(i===mid)x.fillStyle="#f00";else if(i<mid)x.fillStyle="#0f0";else x.fillStyle="#00f";
    x.fillRect(i*w+10,500-h,w-2,h);
    if(i%5===0)x.fillText(arr[i],i*w+10,520);
  }
  // Search step
  if(!done){
    if(arr[mid]===tgt){done=true;}
    else if(arr[mid]<tgt){lo=mid+1;cmp++;}
    else{hi=mid-1;cmp++;}
    mid=(lo+hi)>>1;
    if(lo>hi)done=true;
  }else if(t++>100){lo=0;hi=n-1;mid=(lo+hi)>>1;cmp=0;done=false;tgt=arr[Math.floor(Math.random()*n)];t=0;}
  x.fillStyle="#000";x.font="16px mono";x.fillText("Target:"+tgt,100,50);
  x.fillText("Comparisons:"+cmp,100,80);
  x.fillText("Range:["+lo+","+hi+"]",100,110);
  requestAnimationFrame(draw);
}draw();
</script></body></html>
Results at a glance— every model in this round with score, response time and status.

Who wrote what

ModelBlind scoreLatencyStatus
qwen3.5:9b —26.0 sOK
qwen3-coder:30b —23.2 sOK
qwen3:8b ——harness
mistral-small:24b —78.0 sOK
deepseek-r1:14b —33.2 sOK
qwen3:14b —32.1 sOK
gemma4:26b ——harness
llama3.1:8b —10.4 sOK
command-r:35b —152.3 sOK
qwq:32b —160.7 sOK
deepseek-r1:32b —160.9 sOK

Frontier reference — outside the blind field

These models answered the identical prompt outside the blind field. They are deliberately not scored and not part of the blind comparison — they are there so you can see where a frontier model lands on the same task.

Collected differently from the blind field: the local models run through a plain API harness, the frontier references through a context-free agent, one shot, no retries. Response times are therefore not comparable and are not shown. On two English tasks the reference answer came back in German — an artefact of that harness, flagged on the affected rounds.
Claude Opus 5frontier reference
Show code
<!doctype html>
<html lang="en"><head><meta charset="utf-8"><title>Binary Search Visualizer</title>
<style>
html,body{margin:0;height:100%;background:radial-gradient(1200px 700px at 50% 0%,#141c34,#080b16 70%);
display:flex;align-items:center;justify-content:center;font-family:ui-monospace,Menlo,Consolas,monospace}
canvas{border-radius:14px;box-shadow:0 20px 60px rgba(0,0,0,.6);background:#0b1020}
</style></head><body><canvas id="c"></canvas><script>
const cv=document.getElementById('c'),g=cv.getContext('2d');
const W=980,H=480,DPR=Math.min(2,window.devicePixelRatio||1);
cv.width=W*DPR;cv.height=H*DPR;cv.style.width=W+'px';cv.style.height=H+'px';g.scale(DPR,DPR);
const N=40,PL=50,PR=50,TOP=104,BASE=374,SLOT=(W-PL-PR)/N,BW=SLOT*0.62;
let vals,target,steps,idx,alpha,mLo,mHi,mMid,found,t0=0,last=0,maxV;
function xOf(i){return PL+i*SLOT+SLOT/2}
function init(){
  const s=new Set();while(s.size<N)s.add(4+Math.floor(Math.random()*392));
  vals=[...s].sort((a,b)=>a-b);maxV=vals[N-1];
  target=Math.random()<0.8?vals[Math.floor(Math.random()*N)]:1+Math.floor(Math.random()*400);
  steps=[];found=-1;let lo=0,hi=N-1;
  while(lo<=hi){const mid=(lo+hi)>>1,c=vals[mid]===target?0:(vals[mid]<target?-1:1);
    steps.push({lo:lo,hi:hi,mid:mid,c:c});if(c===0){found=mid;break}
    if(c<0)lo=mid+1;else hi=mid-1}
  if(found<0)steps.push({lo:lo,hi:hi,mid:-1,c:null});
  idx=0;t0=0;alpha=new Array(N).fill(1);
  mLo=xOf(0);mHi=xOf(N-1);mMid=xOf(steps[0].mid);
}
function lerp(a,b,k){return a+(b-a)*k}
function marker(x,y,label,col,dir){
  g.fillStyle=col;g.beginPath();g.moveTo(x,y);g.lineTo(x-6,y+11);g.lineTo(x+6,y+11);g.closePath();g.fill();
  g.font='bold 12px ui-monospace,monospace';g.textAlign='center';g.fillText(label,x+dir*11,y+22);
}
function draw(ts){
  const dt=Math.min(60,ts-last||16);last=ts;if(!t0)t0=ts;
  const cur=steps[idx],end=idx===steps.length-1,D=end?1900:1000;
  if(ts-t0>D){if(!end){idx++;t0=ts}else{init();t0=ts}}
  const st=steps[idx],k=1-Math.exp(-dt/110);
  mLo=lerp(mLo,xOf(Math.min(st.lo,N-1)),k);mHi=lerp(mHi,xOf(Math.max(st.hi,0)),k);
  if(st.mid>=0)mMid=lerp(mMid,xOf(st.mid),k);
  let cmps=0;for(let i=0;i<=idx;i++)if(steps[i].mid>=0)cmps++;
  g.clearRect(0,0,W,H);
  g.fillStyle='#0b1020';g.fillRect(0,0,W,H);
  g.fillStyle='#f1f5f9';g.textAlign='left';g.font='bold 20px ui-monospace,monospace';
  g.fillText('Binary Search',PL,44);
  g.font='13px ui-monospace,monospace';g.fillStyle='#7f8ca8';
  g.fillText('sorted array · n = '+N,PL+186,44);
  g.textAlign='right';g.font='bold 17px ui-monospace,monospace';g.fillStyle='#fbbf24';
  g.fillText('target = '+target,W-PR,32);
  g.fillStyle='#7dd3fc';g.font='13px ui-monospace,monospace';
  g.fillText('comparisons: '+cmps+'   range: '+(st.hi>=st.lo?'['+st.lo+' … '+st.hi+']':'empty'),W-PR,54);
  let msg,mc='#94a3b8';
  if(st.mid<0){msg='target not present — search space empty';mc='#f87171'}
  else if(st.c===0){msg='a[mid] = '+vals[st.mid]+' == target  →  FOUND at index '+st.mid;mc='#4ade80'}
  else if(st.c<0){msg='a[mid] = '+vals[st.mid]+' < '+target+'  →  discard left half';mc='#fbbf24'}
  else {msg='a[mid] = '+vals[st.mid]+' > '+target+'  →  discard right half';mc='#fbbf24'}
  g.textAlign='left';g.fillStyle=mc;g.font='14px ui-monospace,monospace';g.fillText(msg,PL,78);
  g.strokeStyle='#1e293b';g.lineWidth=1;g.beginPath();g.moveTo(PL-14,BASE+.5);g.lineTo(W-PR+14,BASE+.5);g.stroke();
  const pulse=0.62+0.38*Math.sin(ts/150);
  for(let i=0;i<N;i++){
    const on=i>=st.lo&&i<=st.hi?1:0.16;alpha[i]=lerp(alpha[i],on,k);
    const h=8+(vals[i]/maxV)*(BASE-TOP-8),x=xOf(i),y=BASE-h,a=alpha[i];
    const isMid=i===st.mid,hit=isMid&&st.c===0;
    let col=hit?'74,222,128':isMid?'251,191,36':'45,212,191';
    g.fillStyle='rgba('+col+','+(a*(isMid?pulse:0.9))+')';
    g.beginPath();g.roundRect(x-BW/2,y,BW,h,3);g.fill();
    if(isMid){g.strokeStyle='rgba(255,255,255,'+(0.55*a)+')';g.lineWidth=1.4;g.stroke()}
    g.save();g.translate(x,y-7);g.rotate(-Math.PI/2);g.textAlign='left';
    g.font=(isMid?'bold ':'')+'10px ui-monospace,monospace';
    g.fillStyle='rgba('+(isMid?'255,255,255':'203,213,225')+','+(a*0.95)+')';
    g.fillText(vals[i],0,3.5);g.restore();
    if(i%5===0){g.textAlign='center';g.font='9px ui-monospace,monospace';
      g.fillStyle='rgba(100,116,139,'+(0.35+a*0.5)+')';g.fillText(i,x,BASE+13)}
  }
  if(st.hi>=st.lo){
    g.strokeStyle='rgba(125,211,252,.45)';g.lineWidth=2;g.beginPath();
    g.moveTo(mLo-SLOT/2+3,BASE+26);g.lineTo(mHi+SLOT/2-3,BASE+26);g.stroke();
    g.fillStyle='rgba(125,211,252,.10)';g.fillRect(mLo-SLOT/2+3,TOP-14,(mHi-mLo)+SLOT-6,BASE-TOP+14);
    marker(mLo,BASE+32,'low','#7dd3fc',-1);marker(mHi,BASE+32,'high','#7dd3fc',1);
  }
  if(st.mid>=0)marker(mMid,BASE+64,'mid',st.c===0?'#4ade80':'#fbbf24',0);
  g.textAlign='center';g.fillStyle='#475569';g.font='11px ui-monospace,monospace';
  g.fillText('O(log n) — worst case '+Math.ceil(Math.log2(N+1))+' comparisons',W/2,H-12);
  requestAnimationFrame(draw);
}
init();requestAnimationFrame(draw);
</script></body></html>