# 0867. Transpose Matrix

<https://leetcode.com/problems/transpose-matrix>

## Description

Given a 2D integer array `matrix`, return *the **transpose** of* `matrix`.

The **transpose** of a matrix is the matrix flipped over its main diagonal, switching the matrix's row and column indices.

![](https://assets.leetcode.com/uploads/2021/02/10/hint_transpose.png)

**Example 1:**

```
**Input:** matrix = [[1,2,3],[4,5,6],[7,8,9]]
**Output:** [[1,4,7],[2,5,8],[3,6,9]]
```

**Example 2:**

```
**Input:** matrix = [[1,2,3],[4,5,6]]
**Output:** [[1,4],[2,5],[3,6]]
```

**Constraints:**

* `m == matrix.length`
* `n == matrix[i].length`
* `1 <= m, n <= 1000`
* `1 <= m * n <= 105`
* `-109 <= matrix[i][j] <= 109`

## ac

```java
```