Example 1:
(iteration 1): 0 1 2
(iteration 2): 4 6 5   

### Wrong input - missing 3, and second array is not consecutive

Example 2:
(iteration 1): 4 5 6
(iteration 2): 0 1 2 3 4

### Wrong - 4 appears twice

Example 3:
(iteration 1): 4 5 6 7 8
(iteration 2): 0 1 2 3

### this one is OK