leetcode704二分查找

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title: 二分查找

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题目描述

题目链接：二分查找

解题思路

二分模板默写

int search(vector<int>& nums, int target) {
        int left = 0, right = nums.size() - 1;
        int mid;
        while (left <= right) {
            mid = left + ((right - left) >> 1);//记住加括号

            if (nums[mid] == target) return mid;
            if (nums[mid] > target) right = mid - 1;
            if (nums[mid] < target) left = mid + 1;
        }
        return -1;
    }

复杂度分析

• 空间复杂度：o(logn)
• 时间复杂度：o(1)