Auto tetris

by Alex Shnayder

HTML

<div id="auto-tetris"></div>

<div class="description"><span class="results">Squares left: <span id="left">200</span></span><br/><br/>Test UI for tetris algorithm. Just 2 figures: 1x4 and 2x2. Just implement function getColumnNumberForLeftFigureSquare(w, h) that finds the best place for current figure (column number for left square). And wait for the results. Size of tetris: 10 x 20.<br/><br/><a href="http://habrahabr.ru/post/230229/">Post your code here</a></div>

CSS

.description {
    float: left;
    font-size: 12px;
    text-style: italic;
    margin: 10px;
    width: 150px;
}
.results {
    font-size: 18px;
}
#auto-tetris {
    float: left;
    width: 200px;
    height: 400px;
    position: relative;
    border: 1px solid #333;
}
.fig {
    position: absolute;
}
.fig.top {
    top: 0;
    left: 50%;
    background: #333;
}
.fig-1-1 {
    width: 80px;
    height: 20px;
}
.fig-1-1.top {
    margin-left: -40px;
}
.fig-1-2 {
    width: 20px;
    height: 80px;
}
.fig-1-2.top {
    margin-left: -10px;
}
.fig-2-1, .fig-2-2 {
    width: 40px;
    height: 40px;
}
.fig-2-1.top, .fig-2-2.top {
    margin-left: -20px;
}

JavaScript

// Function should return integer from 1 to 10. It is a number of column in which will be left square of figure.
function getColumnNumberForLeftFigureSquare(w, h) {
    function calculateScore(col) {
        if (cols[col] + h > 20 || col + w > 10) {
            return 999;
        }
        
        var score = 0;
        
        for (var i = col; i < col + w; i++) {
            if (cols[i] > cols[col]) {
                return 999;
            }
            
            score += cols[col] - cols[i];
        }
        
        return score;
    }
    
    var bestMatch = {
        col: 0,
        score: cols[0]
    },
        scores = [];
    colScore = 0;
    
    for (var i = 0; i <= cols.length - w; i++) {
        colScore = calculateScore(i);
        scores.push(colScore);
        
        if (colScore < bestMatch.score || (colScore == bestMatch.score && cols[i] < cols[bestMatch.col])) {
            bestMatch = {
                col: i,
                score: colScore
            };
        }
    }
    
    return bestMatch.col + 1;
}

var interval,
    cols = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], // contains filled height for each column (10 columns)
    left = 200,
    speed = 200; // Score

function getRandomInt(min, max) {
    return Math.floor(Math.random() * (max - min)) + min;
}

function getRandomColor() {
    var hex = Math.floor(Math.random() * 0xFFFFFF);
    return "#" + ("000000" + hex.toString(16)).substr(-6);
}

function createRandomFigure() {
    var t = document.getElementById('auto-tetris'),
        l = document.getElementById('left'),
        f = getRandomInt(1, 3), // 1 - 1x4 or 2 - 2x2
        o = getRandomInt(1, 3), // 1 - horizontal or 2 - vertical
        c = 'top fig fig-' + f + '-' + o,
        d = document.createElement('div'),
        h = 2,
        w = 2;

    if (f == 1) {
        if (o == 1) {
            w = 4; h = 1;
        } else {
            w = 1; h = 4;
        }
    }

    d.className = c;
    t.appendChild(d);

   ...