gistfile1.js

var matrix = [
[0, 0, 0, 1, 0, 0, 0],
[0, 0, 0, 1, 0, 0, 0],
[0, 0, 0, 1, 0, 0, 0],
[0, 0, 0, 1, 0, 0, 0],
[0, 0, 0, 1, 1, 0, 0],
[0, 0, 0, 0, 0, 0, 0]
];


function flow (matrix, startPoint) {
    // 2 means water
    matrix[startPoint.y][startPoint.x] = 2;
    var count = 0;
    var reverse = false;
    var loop = false;
    var currentX = startPoint.x;
    var currentY = startPoint.y;
    for (var y = 0; y < matrix.length; y) {
        for (var x = 0; x < matrix[y].length; x) {
            if (matrix[y][x] === 2 && !reverse && !loop) {
                reverse = true;
            }
            reverse ? x-- : x++;
        }
        reverse ? y-- : x++;
    }
    
    return count;

}