给定一个按照升序排列的整数数组 nums,和一个目标值 target。找出给定目标值在数组中的开始位置和结束位置
你的算法时间复杂度必须是 O(log n) 级别
如果数组中不存在目标值,返回 [-1, -1]。
示例 1:
输入: nums = [5,7,7,8,8,10], target = 8
输出: [3,4]
示例 2:
输入: nums = [5,7,7,8,8,10], target = 6
输出: [-1,-1]
class Solution:
def searchRange(self, nums: List[int], target: int) -> List[int]:
if not nums:
return [-1,-1]
start = 0
end = len(nums)-1
while start + 1 < end:
mid = start + int((end-start)/2)
mid_num = nums[mid]
if mid_num < target:
start = mid
elif mid_num > target:
end = mid
elif mid_num == target:
if nums[end] > target:
end -= 1
if nums[start] < target:
start += 1
if nums[start] == target and nums[end] == target:
return [start,end]
if nums[start]!=target and nums[end]!=target:
return [-1,-1]
elif nums[start]!=target :
start += 1
elif nums[end]!=target:
end -= 1
return [start,end]