Binary SearchArray
A mountain array strictly increases up to a single peak and then strictly decreases. Find the index of the peak in O(log n).
Input
Line 1: n. Line 2: the mountain array.
Output
Print the index of the peak element.
Constraints
3 <= n <= 10^5 The array is guaranteed to be a valid mountain with distinct adjacent values.
Example 1
Input
3 0 1 0
Output
1
The peak is the middle element.
Example 2
Input
5 0 2 5 3 1
Output
2
5 is the largest value, at index 2.