寻找峰值—-从中点往高处走

    1. class Solution {
    2. public:
    3.     int findPeakElement(vector<int>& nums) {
    4.         int left=0;
    5.         int right=nums.size()-1;
    6.         while(left<right){
    7.             int mid=left+(right-left)/2;
    8.             if(nums[mid]>nums[mid+1]){
    9.                 right=mid;
    10.             }else{
    11.                 left=mid+1;
    12.             }
    13.         }
    14.         return left;
    15.     }
    16. };
    class Solution {
public:
    int peakIndexInMountainArray(vector<int>& arr) {
        int left=0;
        int right=arr.size()-1;
        while(left<right){
            int mid=left+(right-left)/2;
            if(arr[mid]<arr[mid+1]){
                left=mid+1;
            }else{
                right=mid;
            }
        }
        return left;
    }
};