simple greedy algo for distributing integers (a) in a fixed set of buckets (N) such that the sum of content of the buckets are more or less equal.

greedy.groovy

def a = [1, 2, 3, 4, 5, 6, 7, 8, 9];
def N = 3;
def buckets = [];
for (int i = 0; i < N; i++) {
    buckets[i] = [k: [], t: 0]
}
a.sort { -it }.each { i ->
    def b = buckets[0]
    b.k.push(i)
    b.t += i
    buckets[0] = b;
    buckets.sort { it.t }
}
println(buckets)