// Permutations in js reference (also cool algorithm):
// https://stackoverflow.com/a/41068709
function perm(a){
    if (a.length == 0) return [[]];
    var r = [[a[0]]],
        t = [],
        s = [];
    if (a.length == 1) return r;
    for (var i = 1, la = a.length; i < la; i++){
        for (var j = 0, lr = r.length; j < lr; j++){
            r[j].push(a[i]);
            t.push(r[j]);
            for(var k = 1, lrj = r[j].length; k < lrj; k++){
                for (var l = 0; l < lrj; l++) s[l] = r[j][(k+l)%lrj];
                t[t.length] = s;
                s = [];
            }
        }
        r = t;
        t = [];
    }
    return r;
}

function setHTML(id, html) {
    document.getElementById(id).innerHTML = html;
}

function setValue(id, value) {
    document.getElementById(id).value = value;
}