# 0645. Set Mismatch

https://leetcode.com/problems/set-mismatch

## Description

You have a set of integers `s`, which originally contains all the numbers from `1` to `n`. Unfortunately, due to some error, one of the numbers in `s` got duplicated to another number in the set, which results in **repetition of one** number and **loss of another** number.

You are given an integer array `nums` representing the data status of this set after the error.

Find the number that occurs twice and the number that is missing and return _them in the form of an array_.

**Example 1:**

```
**Input:** nums = [1,2,2,4]
**Output:** [2,3]
```

**Example 2:**

```
**Input:** nums = [1,1]
**Output:** [1,2]
```

**Constraints:**

* `2 <= nums.length <= 104`
* `1 <= nums[i] <= 104`

## ac

```java
```
