题解 | #寻找峰值#

• 二分法查找
• 如果mid的值大于mid+1，说明山峰在左边，令right = mid
• 如果mid的值小于mid+1，说明山峰在右边，令left = mid + 1

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param nums int整型vector 
     * @return int整型
     */
    int findPeakElement(vector<int>& nums) {
        // write code here
        int left = 0, right = nums.size()-1;
        
        while(left < right){
            int mid = left + (right - left)/2;
            if(nums[mid] > nums[mid-1] && nums[mid] > nums[mid+1])
                return mid;//符合要求时，直接return
            if(nums[mid] > nums[mid+1])
                right = mid;
            else if(nums[mid] < nums[mid+1])
                left = mid + 1;
            
        }
        return right;
    }
};