called with [5, 2, 1, 10, 6]
called with [5, 2]
called with [5]
called with [2]
returning [2, 5] 1
called with [1, 10, 6]
called with [1]
called with [10, 6]
called with [10]
called with [6]
returning [6, 10] 1
returning [1, 6, 10] 1
returning [1, 2, 5, 6, 10] 4
4