algorithm-base/animation-simulation/二分查找及其变种/leetcode35搜索插入位置.md
2021-03-20 12:38:26 +08:00

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### leetcode35搜索插入位置
#### 题目描述
> 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。
>
> 你可以假设数组中无重复元素。
示例 1:
> 输入: [1,3,5,6], 5
> 输出: 2
示例 2:
> 输入: [1,3,5,6], 2
> 输出: 1
示例 3:
> 输入: [1,3,5,6], 7
> 输出: 4
示例 4:
> 输入: [1,3,5,6], 0
> 输出: 0
#### 题目解析
这个题目完全就和咱们的二分查找一样,只不过有了一点改写,那就是将咱们的返回值改成了 left具体实现过程见下图
![搜索插入位置](https://img-blog.csdnimg.cn/img_convert/d806cb5199c4baeebc62bebe29d7eded.gif)
#### 题目代码
```java
class Solution {
public int searchInsert(int[] nums, int target) {
int left = 0, right = nums.length-1;
//注意循环条件
while (left <= right) {
//求mid
int mid = left + ((right - left ) >> 1);
//查询成功
if (target == nums[mid]) {
return mid;
//右区间
} else if (nums[mid] < target) {
left = mid + 1;
//左区间
} else if (nums[mid] > target) {
right = mid - 1;
}
}
//返回插入位置
return left;
}
}
```