leetcode讲解--852. Peak Index in a Mountain Array

852. Peak Index in a Mountain Array

Let's call an array A a mountain if the following properties hold:

A.length >= 3
There exists some 0 < i < A.length - 1 such that A[0] < A[1] < ... A[i-1] < A[i] > A[i+1] > ... > A[A.length - 1]
Given an array that is definitely a mountain, return any i such that A[0] < A[1] < ... A[i-1] < A[i] > A[i+1] > ... > A[A.length - 1].

Example 1:

Input: [0,1,0]
Output: 1

Example 2:

Input: [0,2,1,0]
Output: 1

Note:

1. 3 <= A.length <= 10000
2. 0 <= A[i] <= 10^6
3. A is a mountain, as defined above.

这题非常简单，就是求数组中的最大值

java代码

class Solution {
    public int peakIndexInMountainArray(int[] A) {
        int max = A[0];
        for(int i=1;i<A.length;i++){
            if(max>A[i]){
                return i-1;
            }else{
                max=A[i];
            }
        }
        return 0;
    }
}