# 1559. Detect Cycles in 2D Grid

https://leetcode.com/problems/detect-cycles-in-2d-grid

## Description

Given a 2D array of characters `grid` of size `m x n`, you need to find if there exists any cycle consisting of the **same value** in `grid`.

A cycle is a path of **length 4 or more** in the grid that starts and ends at the same cell. From a given cell, you can move to one of the cells adjacent to it - in one of the four directions (up, down, left, or right), if it has the **same value** of the current cell.

Also, you cannot move to the cell that you visited in your last move. For example, the cycle `(1, 1) -> (1, 2) -> (1, 1)` is invalid because from `(1, 2)` we visited `(1, 1)` which was the last visited cell.

Return `true` if any cycle of the same value exists in `grid`, otherwise, return `false`.

**Example 1:**

![](https://assets.leetcode.com/uploads/2020/07/15/1.png)

```
**Input:** grid = [["a","a","a","a"],["a","b","b","a"],["a","b","b","a"],["a","a","a","a"]]
**Output:** true
**Explanation:** There are two valid cycles shown in different colors in the image below:
![](https://assets.leetcode.com/uploads/2020/07/15/11.png)
```

**Example 2:**

![](https://assets.leetcode.com/uploads/2020/07/15/22.png)

```
**Input:** grid = [["c","c","c","a"],["c","d","c","c"],["c","c","e","c"],["f","c","c","c"]]
**Output:** true
**Explanation:** There is only one valid cycle highlighted in the image below:
![](https://assets.leetcode.com/uploads/2020/07/15/2.png)
```

**Example 3:**

![](https://assets.leetcode.com/uploads/2020/07/15/3.png)

```
**Input:** grid = [["a","b","b"],["b","z","b"],["b","b","a"]]
**Output:** false
```

**Constraints:**

* `m == grid.length`
* `n == grid[i].length`
* `1 <= m, n <= 500`
* `grid` consists only of lowercase English letters.

## ac

```java
```
