代码随想录——二分查找（Leetcode704）

题目链接

看到题目后第一想法：

class Solution {
    public int search(int[] nums, int target) {
        int index = -1;
        for(int i = 0; i < nums.length; i++){
            if(target == nums[i]){
                index = i;
                break;
            }
        }
        return index;
    }
}

优化代码（本题目的应是想要使用二分查找）：

class Solution {
    public int search(int[] nums, int target) {
        int len = nums.length;
        int left = 0;
        int right = len - 1;
        int index = -1;
        while(left <= len / 2){
            if(nums[left] == target){
                index = left;
                break;
            }else {
                left++;
            }
            if(nums[right] == target){
                index = right;
                break;
            }else {
                right--;
            }
        }
        return index;
    }
}