33. 搜索旋转排序数组 @Python @Go

原题

https://leetcode.cn/problems/search-in-rotated-sorted-array/description/

思路

二分查找

复杂度

时间：O(log(n))
空间：O(1)

Python代码

class Solution:
    def search(self, nums: List[int], target: int) -> int:
        l, r = 0, len(nums) - 1 
        while l <= r:
            mid = (l + r) // 2 
            if nums[mid] == target:
                return mid
            elif nums[mid] < nums[r]:
                # 在[mid, r]区间升序
                if nums[mid] < target and target <= nums[r]:
                    l = mid + 1
                else:
                    r = mid - 1 
            else:
                # 在[l, mid]区间升序
                if nums[l] <= target and target < nums[mid]:
                    r = mid - 1 
                else:
                    l = mid + 1 
        return -1 

        

Go代码

func search(nums []int, target int) int {
	l, r := 0, len(nums)-1
	for l <= r {
		mid := (l + r) / 2
		if nums[mid] == target {
			return mid
		} else if nums[mid] < nums[r] {
			// 在[mid, r]区间升序
			if nums[mid] < target && target <= nums[r] {
				l = mid + 1
			} else {
				r = mid - 1
			}
		} else {
			// 在[l, mid]区间升序
			if nums[l] <= target && target < nums[mid] {
				r = mid - 1
			} else {
				l = mid + 1
			}
		}
	}
	return -1
}