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

分析:
最近的easy题越来越弱智了，A是一个山，而山的定义是存在i满足 A[0] < A[1] < … A[i-1] < A[i] > A[i+1] > … > A[A.length - 1]
所以显然A[i]就是A中最大值

1
2
3
4
5
6
7
8
9
10
11
12

class (object):
    def peakIndexInMountainArray(self, A):
        """
        :type A: List[int]
        :rtype: int
        """
        return A.index(max(A))

O(n) time, O(1) space
32 / 32 test cases passed.
difficulty: easy
Runtime: 61 ms