Project Euler problem 11 - riemann79/hello-world GitHub Wiki

var grid = [],
    nrows = 0,
    ncols = 0,
    theLargestProduct = 1;

for(var i = 0; i < nrows; i++) {
    for(var j = 0; j < ncols; j++) {

        var prod = Math.max.apply(null, [
            get(i, j) * get(i, j+1) * get(i, j+2) * get(i, j+3),        // right
            get(i, j) * get(i+1, j) * get(i+2, j) * get(i+3, j),        // down
            get(i, j) * get(i+1, j+1) * get(i+2, j+2) * get(i+3, j+3),  // diag right-down
            get(i, j) * get(i+1, j-1) * get(i+2, j- 2) * get(i+3, j-3)  // diag left-down
        ]);

        if(prod > theLargestProduct) {
            theLargestProduct = prod;
        }
    }
}

function get(i, j) {
    if(i < 0 || i >= nrows || j < 0 || j >= ncols) {
        // A convenience value when indexes are out of bounds.
        return 0;
    }

    return grid[i * ncols + j];
}