Peak Index in a Mountain Array

arraybinary search

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

Input: arr = [0,1,0]
Output: 1

Example 2

Input: arr = [0,2,1,0]
Output: 1

Example 3

Input: arr = [0,10,5,2]
Output: 1

3 <= arr.length <= 10 ^5

0 <= arr[i] <= 10 ^6

arr is guaranteed to be a mountain array.

🤔

Medium

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicBinary Search