【leetcode 704】二分查找

class Solution:
    def search(self, nums: List[int], target: int) -> int:
        left,right = 0, len(nums)-1
        # 循环结束的条件是左右指针相遇
        while left<=right:
            mid = (left+right)//2
            if target > nums[mid]:
                left = mid+1
            elif target < nums[mid]:
                right = mid-1
            else:
                return mid
        return -1