34. Find First and Last Position of Element in Sorted Array
Đề Bài
Given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value.
If target is not found in the array, return [-1, -1].
You must write an algorithm with O(log n) runtime complexity.
Example 1:
Input: nums = [5,7,7,8,8,10], target = 8 Output: [3,4]
Example 2:
Input: nums = [5,7,7,8,8,10], target = 6 Output: [-1,-1]
Example 3:
Input: nums = [], target = 0 Output: [-1,-1]
Constraints:
0 <= nums.length <= 105-109 <= nums[i] <= 109numsis a non-decreasing array.-109 <= target <= 109
Thuật Toán & Kỹ Thuật
⏱️ Thời gian
O(log n)
💾 Không gian
O(n)
Lời Giải
Python
0034-find-first-and-last-position-of-element-in-sorted-array.py
class Solution:
def searchRange(self, nums: List[int], target: int) -> List[int]:
left = bisect_left(nums, target)
right = bisect_left(nums, target + 1)
n = len(nums)
if left == n or right - 1 == n or nums[left] != target or nums[right - 1] != target:
return [-1, -1]
return [left, right - 1]