leetcode 852
和 162 一毛一样, 意义何在?
class Solution:
def peakIndexInMountainArray(self, arr: List[int]) -> int:
start = 0
end = len(arr) - 1
while start < end:
mid = (start + end) // 2
if arr[mid] < arr[mid + 1]:
start = mid + 1
else:
end = mid
return start