Given an array A, partition it into two (contiguous) subarrays left and right so that: Every element in left is less than or equal to every element in right. left and right are non-empty. left has the smallest possible size. Return the length of left after such a partitioning. It is guaranteed that such a partitioning exists. Example 1: Input: [5,0,3,8,6] Output: 3 Explanation: left = [5,0,3], right = [8,6] Example 2: Input: [1,1,1,0,6,12] Output: 4 Explanation: left = [1,1,1,0], right = [6,12] Note: 2 <= A.length <= 30000 0 <= A[i] <= 10^6 It is guaranteed there is at least one way to partition A as described.