Find the peak (two points)

Title: https://leetcode-cn.com/problems/find-peak-element/

class Solution {
public:
    int findPeakElement(vector<int>& nums) {
        /*
        *给定一个输入数组 nums，其中 nums[i] ≠ nums[i+1]，
        *找到峰值元素并返回其索引
        */
        int n = nums.size();
        int l = 0,r = n-1;
        while(l < r) {
            int m = (l+r)/2;
            if(nums[m] > nums[m+1]) r = m;
            else l = m+1;
        }
        return l;
    }
};