75. 寻找峰值

class Solution:
    """
    @param A: An integers array.
    @return: return any of peek positions.
    """
    def findPeak(self, A):
        # write your code here
        #二分法
        start,end = 0, len(A) - 1
        while start < end:
            mid = (start + end) // 2
            
            if A[mid] < A[mid - 1]:
                end = mid
            elif A[mid] < A[mid + 1]:
                start = mid
            else:
                return mid
                
        if (A[start] < A[end]):
            return end
        else:
            return start