Split number into 4 random numbers

Question

I want to split 10 into an array of 4 random numbers, but neither can be 0 or higher than 4. For example [1,2,3,4],

Answer 1

Basically you need the partitions (See https://en.wikipedia.org/wiki/Partition_(number_theory)) of 10 and apply your conditions on the resulting set.

// Partition generator taken from 
// https://gist.github.com/k-hamada/8aa85ac9b334fb89ac4f

function* partitions(n) {

    if (n <= 0) throw new Error('positive integer only');
    yield [n];

    var x = new Array(n);
    x[0] = n;
    for (var i = 1; i < n; i++) x[i] = 1;

    var m = 0, h = 0, r, t;
    while (x[0] != 1) {
        if (x[h] == 2) {
            m += 1;
            x[h] = 1;
            h -= 1;
        } else {
            r = x[h] - 1;
            x[h] = r;

            t = m - h + 1;
            while (t >= r) {
                h += 1;
                x[h] = r;
                t -= r;
            }
            m = h + (t !== 0 ? 1 : 0);
            if (t > 1) {
                h += 1;
                x[h] = t;
            }
        }
        yield x.slice(0, m + 1);
    }
}

results = [];
// Get all possible partitions for your number
for (var partition of partitions(10)) {
    // Apply your conditions (must be 4 numbers, none of them greater than 4)
    if(partition.length != 4 || partition.some((x) => x > 4)) continue;
    results.push(partition);
}
console.log(results);