0034-leetcode演算法實現之查詢元素位置-find-first-and-last-position-of-element-in-sorted-array-python&golang實現
阿新 • • 發佈:2021-10-14
給定一個按照升序排列的整數陣列 nums,和一個目標值 target。找出給定目標值在陣列中的開始位置和結束位置。
如果陣列中不存在目標值 target,返回[-1, -1]。
進階:
你可以設計並實現時間複雜度為O(log n)的演算法解決此問題嗎?
示例 1:
輸入:nums = [5,7,7,8,8,10], target = 8
輸出:[3,4]
示例2:
輸入:nums = [5,7,7,8,8,10], target = 6
輸出:[-1,-1]
示例 3:
輸入:nums = [], target = 0
輸出:[-1,-1]
來源:力扣(LeetCode)
連結:https://leetcode-cn.com/problems/find-first-and-last-position-of-element-in-sorted-array
python
class Solution: def searchRange(self, nums: [int], target: int) -> [int]: def search(nums: [int], target: int) -> int: left, right = 0, len(nums) while left < right: mid = int((left+right)/2) if nums[mid] >= target: right = mid else: left = mid + 1 return left # 找到第一個=target的位置 leftIdx = search(nums, target) # 找到第一個 > target的位置 rightIdx = search(nums, target+1) if leftIdx == len(nums) or nums[leftIdx] != target: return [-1, -1] return [leftIdx, rightIdx-1] if __name__ == "__main__": nums1 = [1,3] target1 = 2 nums2 = [1,3,3,3,3,3,3,3,5,5,6] target2 = 5 test = Solution() print(test.searchRange(nums1,target1)) # [-1, -1] print(test.searchRange(nums2,target2)) # [8, 9]
golang
func main() { var nums = []int{1, 3, 3, 3, 3, 3, 3, 3, 5, 5, 6} var target int = 5 res := searchRange(nums, target) fmt.Println(res) } func searchRange(nums []int, target int) []int { //第一個=target的位置 leftIdx := search(nums, target) rightIdx := search(nums, target+1) if leftIdx == len(nums) || nums[leftIdx] != target { return []int{-1, -1} } return []int{leftIdx, rightIdx - 1} } func search(nums []int, target int) int { var left int = 0 var right int = len(nums) for left < right { var mid int = (left + right) / 2 if nums[mid] >= target { right = mid } else { left = mid + 1 } } return left }