35搜索插入位置

原题：

35. 搜索插入位置 - 力扣（LeetCode）

给定一个排序数组和一个目标值，在数组中找到目标值，并返回其索引。如果目标值不存在于数组
中，返回它将会被按顺序插入的位置。

我的思路

考虑问题要细节

1、空数组处理

public int searchInsert(int[] nums, int target) {if (nums == null || nums.length == 0) {return 0;}return search(nums, target, 0, nums.length - 1);
}

代码实现

class Solution {public int searchInsert(int[] nums, int target) {if (nums == null || nums.length == 0) {return 0;}return search(nums,target,0,nums.length-1);}public static int search(int[] nums, int target,int low,int high){if(low>=high){if(target>nums[low]){return low+1;}return low;}int mid = (low+high)/2;if(nums[mid]==target){return mid;}else if(nums[mid]>target){return search(nums,target,low,mid-1);}else{return search(nums,target,mid+1,high);}}
}

官方思路：

class Solution {public int searchInsert(int[] nums, int target) {int n = nums.length;int left = 0, right = n - 1, ans = n;while (left <= right) {int mid = ((right - left) >> 1) + left;if (target <= nums[mid]) {ans = mid;right = mid - 1;} else {left = mid + 1;}}return ans;}
}