A to Z in 10x10

gistfile1.js

/*
10 x 10
A-Z ( 65 -> 90)

output something like this

* * * * * * * * * *
* * * * * * * * * *
* * * * * * * * * *
* J I * * * * * * *
* K H * * * * * * *
M L G F E * * * * *
N A B C D * * * * *
O V U * * * * * * *
P W T * * * * * * *
Q R S * * * * * * *

*/

var n = 10;

// start point
var x = getRandomNum(n),
    y = getRandomNum(n);
    
var s = 65,
    e = 90;
    
var matrix = [];
for(var ni=0; ni<n; ni++) {
    matrix[ni] = new Array(n);
}
    
matrix[x][y] = String.fromCharCode(s);
s++;

while ( s <= e) {
    var next = getNextLocation(x, y);
    //console.log(next);
    if (next === null) break;
    
    x = next[0];
    y = next[1];
    matrix[x][y] = String.fromCharCode(s++);
}

for (var i=0; i<n; i++) {
    var str = '';
    for (var j=0; j<n; j++) {
        if (matrix[i][j]) {
            str += matrix[i][j] + ' ';
        } else {
            str += '* ';
        }
    }
    console.log(str);
}
   
    
function getRandomNum(max) {
    return Math.round(Math.random() * (max - 1));
}


function getNextLocation(x, y) {
    var alternates = [];    
    
    if ((x-1 >= 0) && !matrix[x-1][y]) alternates.push([x-1, y]);
    if ((x+1 < n) && !matrix[x + 1][y]) alternates.push([x+1, y]);
    if ((y-1 >= 0) && !matrix[x][y-1]) alternates.push([x, y-1]);
    if ((y+1 < n) && !matrix[x][y+1]) alternates.push([x, y+1]);
    
    if (alternates.length == 0) return null;
    
    return alternates[getRandomNum(alternates.length)];
}

//@ sourceURL=A_Z_in_10x10