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# Find all Duplicate Numbers (easy)

## Problem Statement

We are given an unsorted array containing `n`

numbers taken from the range `1 to n`

. The array has some numbers appearing twice, **find all these duplicate numbers using constant space**.

**Example 1**:

```
Input: [3, 4, 4, 5, 5]
Output: [4, 5]
```

**Example 2**:

```
Input: [5, 4, 7, 2, 3, 5, 3]
Output: [3, 5]
```

**Constraints:**

`nums.length == n`

- 1 <= n <= 10^5
`1 <= nums[i] <= n`

- Each element in
`nums`

appears`once`

or`twice`

.

## Try it yourself

Try solving this question here:

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