Project Euler 11

function productVert(arr,i,j) {
    return arr[i][j] * arr[i+1][j] * arr[i+2][j] * arr[i+3][j];
}

function productHor(arr,i,j) {
    return arr[i][j] * arr[i][j+1] * arr[i][j+2] * arr[i][j+3];
}

function productDiagL(arr,i,j) {
    return arr[i][j] * arr[i+1][j+1] * arr[i+2][j+2] * arr[i+3][j+3];
}

function productDiagR(arr,i,j) {
    return arr[i][j] * arr[i+1][j-1] * arr[i+2][j-2] * arr[i+3][j-3];
}

var myArr = [];
myArr[0] = [08, 02, 22, 97, 38, 15, 00, 40, 00, 75, 04, 05, 07, 78, 52, 12, 50, 77, 91, 08];
myArr[1] = [49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 04, 56, 62, 00];
myArr[2] = [81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 03, 49, 13, 36, 65];
myArr[3] = [52, 70, 95, 23, 04, 60, 11, 42, 69, 24, 68, 56, 01, 32, 56, 71, 37, 02, 36, 91];
myArr[4] = [22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80];
myArr[5] = [24, 47, 32, 60, 99, 03, 45, 02, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50];
myArr[6] = [32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70];
myArr[7] = [67, 26, 20, 68, 02, 62, 12, 20, 95, 63, 94, 39, 63, 08, 40, 91, 66, 49, 94, 21];
myArr[8] = [24, 55, 58, 05, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72];
myArr[9] = [21, 36, 23, 09, 75, 00, 76, 44, 20, 45, 35, 14, 00, 61, 33, 97, 34, 31, 33, 95];
myArr[10] = [78, 17, 53, 28, 22, 75, 31, 67, 15, 94, 03, 80, 04, 62, 16, 14, 09, 53, 56, 92];
myArr[11] = [16, 39, 05, 42, 96, 35, 31, 47, 55, 58, 88, 24, 00, 17, 54, 24, 36, 29, 85, 57];
myArr[12] = [86, 56, 00, 48, 35, 71, 89, 07, 05, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58];
myArr[13] = [19, 80, 81, 68, 05, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77, 04, 89, 55, 40];
myArr[14] = [04, 52, 08, 83, 97, 35, 99, 16, 07, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66];
myArr[15] = [88, 36, 68, 87, 57, 62, 20, 72, 03, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69];
myArr[16] = [04, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18, 08, 46, 29, 32, 40, 62, 76, 36];
myArr[17] = [20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74, 04, 36, 16];
myArr[18] = [20, 73, 35, 29, 78, 31, 90, 01, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57, 05, 54];
myArr[19] = [01, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 01, 89, 19, 67, 48];

var answer = 0;

for (i=0; i<20; i++) {
    for (j=0; j<20; j++) {
        var vert = 0;
        var hor = 0;
        var diagR = 0;
        var diagL = 0;

        if (i <= 16) {
            if (j <= 2) {
                vert = productVert(myArr,i,j);
                hor = productHor(myArr,i,j);
                diagR = productDiagR(myArr,i,j);
            }
            else if (j >= 17) {
                vert = productVert(myArr,i,j);
                hor = productHor(myArr,i,j);
                diagL = productDiagL(myArr,i,j);
            }
            else {
                vert = productVert(myArr,i,j);
                hor = productHor(myArr,i,j);
                diagL = productDiagL(myArr,i,j);
                diagR = productDiagR(myArr,i,j);
            }
        }
        else {
            if (j <= 16) {
                hor = productHor(myArr,i,j);
            }
        }

        max = Math.max(vert, hor, diagL, diagR);

        if (max > answer) {
            answer = max;
        }
    }
}

console.log(answer);
Written on August 10, 2016