[Leetcode] Find Peak Element

Find Peak Element

A peak element is an element, which is greater than its neighbors.

Given an input array where num[i] ≠ num[i+1] , the find a peak element and return its index.

The array may be contain multiple peaks, in this case return the index to any one of the peaks is fine.

May imagine num[-1] = num[n] = -∞ .

For example, in array [1, 2, 3, 1] , 3 is a peak element and your function should return the index number 2.

Click to show spoilers.

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

The problem is to find the maximum value of the array in a disguised way.

Two-point search, Time complexity O (n).

1 classSolution {2  Public:3     intFindpeakelement (vector<int>&nums) {4         intleft=0, Right=nums.size ()-1;5          while(left<Right )6         {7             intMid = (left+right)/2;8             if(nums[mid]<nums[mid+1])9             {Tenleft = mid+1; One             } A             Else -             { -right =mid; the             } -         } -         returnLeft ; -     } +};

[Leetcode] Find Peak Element