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# 35.Search-Insert-Position

## 35. Search Insert Position

## 题目地址

<http://www.lintcode.com/problem/search-insert-position/description>

<https://www.jiuzhang.com/solutions/search-insert-position/>

## 题目描述

```
Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.

You may assume NO duplicates in the array.

Example
[1,3,5,6], 5 → 2

[1,3,5,6], 2 → 1

[1,3,5,6], 7 → 4

[1,3,5,6], 0 → 0

Challenge
O(log(n)) time
```

## 代码

Appraoch 1: Find the first position

```java
public class Solution {
    public int searchInsert(int[] A, int target) {
    if (A == null | A.length == 0) return 0;

    int start = 0;
    int end = A.length - 1;

    while (start + 1 < end) {
      int mid = start + (end - start) / 2;
      if (A[mind] == target) {
        return mid;
      } else if (A[mid] < target) {
        start = mid;
      } else {
        end = mid;
      }
    }

    if (A[start] >= target) {
      return start;
    } else if (A[end] >= target) {
      return end;
    } else {
      return end + 1;
    }

    /// approach 2:
    if (target < A[0]) return 0;

    if (A[end] == target) return end;
    if (A[start] == target) return start;
    if (A[end] < target)    return end + 1;

    return start + 1;

  }

}
```