704. 二分查找

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class Solution:
    def search(self, nums: List[int], target: int) -> int:
        # 迭代循环方法
        # left = 0
        # right = len(nums)-1
        # while (left<=right):
        #     half = left+(right-left)//2
        #     if nums[half]>target:
        #         right = half-1
        #     elif nums[half]<target:
        #         left = half+1
        #     else:
        #         return half
        # return -1
        # 递归方法
        def search_II(left,right):
            while left<=right:
                half = (left+right)//2
                if nums[half]==target:
                    return half 
                elif nums[half]>target:
                    return search_II(left,half-1)
                else:
                    return search_II(half+1,right)
            return -1
        return search_II(left=0,right=len(nums)-1)