leetcode中等162寻找峰值

Posted 2021-10-05 qq_40707462

注意：[1,2] 输出1
[1]输出0

思路：要求时间复杂度log(n)，必须二分
相当于找函数的极值

class Solution:
    def findPeakElement(self, nums: List[int]) -> int:
        left=0
        right=len(nums)-1
        while(left<right):
            mid=(left+right)//2
            if(nums[mid]>nums[mid+1]):
                right=mid
            else:
                left=mid+1
            
        return left

class Solution {
    public int findPeakElement(int[] nums) {
        int left=0,right=nums.length-1;
        while(left<right){
            int mid=(left+right)/2;
            if(nums[mid]>nums[mid+1]){
                right=mid;
            }else{
                left=mid+1;
            }
        }
        return left;
    }
}