Given an array A of distinct integers sorted in ascending order, return the
smallest index i that satisfies A[i] == i. Return
-1 if no such i exists.
Example 1:
Input: [-10,-5,0,3,7]
Output: 3
Explanation:
For the given array, A[0] = -10, A[1] = -5, A[2] = 0, A[3] = 3, thus the output is 3.
Example 2:
Input: [0,2,5,8,17]
Output: 0
Explanation:
A[0] = 0, thus the output is 0.
Example 3:
Input: [-10,-5,3,4,7,9] Output: -1 Explanation: There is no suchithatA[i] = i, thus the output is -1.
Note:
1 <= A.length < 10^4-10^9 <= A[i] <= 10^9