【Leetcode_easy】852. Peak Index in a Mountain Array

problem

852. Peak Index in a Mountain Array

solution1:

class Solution {
public:
    int peakIndexInMountainArray(vector<int>& A) {
        return max_element(A.begin(), A.end())-A.begin();
    }
};

solution2:

class Solution {
public:
    int peakIndexInMountainArray(vector<int>& A) {
        for(int i=; i<A.size()-; ++i)
        {
            if(A[i]>A[i+]) return i;
        }
        return ;//err..
    }
};

solution3:

class Solution {
public:
    int peakIndexInMountainArray(vector<int>& A) {
        int left = , right = A.size()-;
        int mid = ;
        while(left<right)
        {
            mid = left + (right-left)/;
            if(A[mid]<A[mid+]) left = mid + ;//err...
            else right = mid;//errr...
        }
        return right;//err..
    }
};

参考

1. Leetcode_easy_852. Peak Index in a Mountain Array;

2. grandyang;

3. discuss;

完