1. Given blocks = [2, 6, 8, 5], the function should return 2.
If starting from blocks[o], the first frog can stay where it is and the second frog can jump to blocks[2] (but not to blocks[3]).
2. Given blocks = [1, 5, 5, 2, 6], the function should return 3.
If starting from blocks[3], the first frog can jump to blocks[1], but not blocks[o], and the second frog can jump to blocks[4].
3. Given blocks = [1, 1], the function should return 1.
If starting from blocks[1], the first frog can jump to blocks[o] and the second frog can stay where it is. Starting from blocks[0] would result in the same distance.