# 852.Peak Index in A Mountain Array

**852.Peak Index in a Mountain Array**

> 我们把符合下列属性的数组 A 称作山脉： A.length >= 3 存在 0 < i < A.length - 1 使得A\[0] < A\[1] < ... A\[i-1] < A\[i] > A\[i+1] > ... > A\[A.length - 1] 给定一个确定为山脉的数组，返回任何满足 A\[0] < A\[1] < ... A\[i-1] < A\[i] > A\[i+1] > ... > A\[A.length - 1] 的 i 的值。

示例 1：

```
输入：[0,1,0]
输出：1
```

示例 2：

```
输入：[0,2,1,0]
输出：1
```

提示：

```
3 <= A.length <= 10000
0 <= A[i] <= 10^6
A 是如上定义的山脉
```

方法：这题太简单，找出最大值索引即可。

```
class Solution {
public:
    int peakIndexInMountainArray(vector<int>& A) {
        int n=A.size();
        int k=0;
        for (int i=0;i<n;i++)
            k=  (A[i] > A[k]) ?i : k;
        return k;
    }
};
```


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