Peak Index in a Mountain Array
You are given an integer mountain array arr of length n where the values increase to a peak element and then decrease.
Return the index of the peak element.
Your task is to solve it in O(log(n)) time complexity.
Example 1
# 0 1 0
Input
arr = [0,1,0]Output
1The peak element is 1 at index 1.
Example 2
# # # 0 2 1 0
Input
arr = [0,2,1,0]Output
1The peak element is 2 at index 1.
Constraints
- 3 <= arr.length <= 10^5
- 0 <= arr[i] <= 10^6
- arr is guaranteed to be a mountain array.