题目
A peak element is an element that is strictly greater than its neighbors.
Given a 0-indexed integer array nums, find a peak element, and return its index. If the array contains multiple peaks, return the index to any of the peaks.
You may imagine that nums[-1] = nums[n] = -∞. In other words, an element is always considered to be strictly greater than a neighbor that is outside the array.
You must write an algorithm that runs in O(log n) time.
解题思路
代码
class Solution:
def findPeakElement(self, nums: List[int]) -> int:
l, r = 0, len(nums) - 1
while l <= r:
if l == r:
return l
m = (l + r) // 2
if nums[m - 1] < nums[m] > nums[m + 1]:
return m
if nums[m] < nums[m + 1]:
l = m + 1
else:
r = m - 1
