Find Peak Element
Desicription
A peak element is an element that is greater than its neighbors.
Given an input array nums, where nums[i] ≠ nums[i 1], find a peak element and return its index.
The array may contain multiple peaks, in that case return the index to any one of the peaks is fine.
You may imagine that nums[-1] = nums[n] = -∞.
Example 1:
代码语言：javascript复制Input: nums = [1,2,3,1]
Output: 2
Explanation: 3 is a peak element and your function should return the index number 2.Example 2:
代码语言：javascript复制Input: nums = [1,2,1,3,5,6,4]
Output: 1 or 5
Explanation: Your function can return either index number 1 where the peak element is 2,
or index number 5 where the peak element is 6.Note:
Your solution should be in logarithmic complexity.
Solution
代码语言：javascript复制class Solution {
public:
int findPeakElement(vector<int>& nums) {
int left = 0;
int right = nums.size() - 1;
while(left < right) {
int mid1 = (left right) >> 1;
int mid2 = mid1 1;
if(nums[mid1] < nums[mid2])
left = mid2;
else
right = mid1;
}
return left;
}
};
