"""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"""

A = [0, 2, 1, 0]


def peakIndexInMountainArray(self, A):
    """
    :type A: List[int]
    :rtype: int
    """
    for i in range(len(A) - 1):
        if A[i] > A[i + 1]:
            return i