called with [9, 1, 10, 3, 9]
called with [9, 1]
called with [9]
called with [1]
returning [1, 9] 1
called with [10, 3, 9]
called with [10]
called with [3, 9]
called with [3]
called with [9]
returning [3, 9] 0
returning [3, 9, 10] 2
returning [1, 3, 9, 9, 10] 4
4