<p>Given a 2D array of characters <code>grid</code> of size <code>m x n</code>, you need to find if there exists any cycle consisting of the <strong>same value</strong> in <code>grid</code>.</p>

<p>A cycle is a path of <strong>length 4 or more</strong> 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 <strong>same value</strong> of the current cell.</p>

<p>Also, you cannot move to the cell that you visited in your last move. For example, the cycle <code>(1, 1) -&gt; (1, 2) -&gt; (1, 1)</code> is invalid because from <code>(1, 2)</code> we visited <code>(1, 1)</code> which was the last visited cell.</p>

<p>Return <code>true</code> if any cycle of the same value exists in <code>grid</code>, otherwise, return <code>false</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<p><strong><img alt="" src="https://assets.leetcode.com/uploads/2020/07/15/1.png" style="width: 231px; height: 152px;" /></strong></p>

<pre>
<strong>Input:</strong> grid = [[&quot;a&quot;,&quot;a&quot;,&quot;a&quot;,&quot;a&quot;],[&quot;a&quot;,&quot;b&quot;,&quot;b&quot;,&quot;a&quot;],[&quot;a&quot;,&quot;b&quot;,&quot;b&quot;,&quot;a&quot;],[&quot;a&quot;,&quot;a&quot;,&quot;a&quot;,&quot;a&quot;]]
<strong>Output:</strong> true
<strong>Explanation: </strong>There are two valid cycles shown in different colors in the image below:
<img alt="" src="https://assets.leetcode.com/uploads/2020/07/15/11.png" style="width: 225px; height: 163px;" />
</pre>

<p><strong class="example">Example 2:</strong></p>

<p><strong><img alt="" src="https://assets.leetcode.com/uploads/2020/07/15/22.png" style="width: 236px; height: 154px;" /></strong></p>

<pre>
<strong>Input:</strong> grid = [[&quot;c&quot;,&quot;c&quot;,&quot;c&quot;,&quot;a&quot;],[&quot;c&quot;,&quot;d&quot;,&quot;c&quot;,&quot;c&quot;],[&quot;c&quot;,&quot;c&quot;,&quot;e&quot;,&quot;c&quot;],[&quot;f&quot;,&quot;c&quot;,&quot;c&quot;,&quot;c&quot;]]
<strong>Output:</strong> true
<strong>Explanation: </strong>There is only one valid cycle highlighted in the image below:
<img alt="" src="https://assets.leetcode.com/uploads/2020/07/15/2.png" style="width: 229px; height: 157px;" />
</pre>

<p><strong class="example">Example 3:</strong></p>

<p><strong><img alt="" src="https://assets.leetcode.com/uploads/2020/07/15/3.png" style="width: 183px; height: 120px;" /></strong></p>

<pre>
<strong>Input:</strong> grid = [[&quot;a&quot;,&quot;b&quot;,&quot;b&quot;],[&quot;b&quot;,&quot;z&quot;,&quot;b&quot;],[&quot;b&quot;,&quot;b&quot;,&quot;a&quot;]]
<strong>Output:</strong> false
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>m == grid.length</code></li>
	<li><code>n == grid[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 500</code></li>
	<li><code>grid</code> consists only of lowercase English letters.</li>
</ul>

class Solution {
public:
    bool containsCycle(vector<vector<char>>& grid) {
        int m = grid.size();
        int n = grid[0].size();

        vector<vector<bool>> visited(m,vector<bool>(n, false));
        vector<vector<bool>> rec(m,vector<bool>(n, false));
        vector<vector<int>> dir = {{-1,0},{1,0},{0,-1},{0,1}};

        for(int i=0;i<m;i++) {
            for(int j=0;j<n;j++) {
                if(!visited[i][j]) {
                    if(isCyclic(grid,visited,rec,dir,i,j,-1,-1,grid[i][j]))
                        return true;
                }
            }
        }
        return false;
    }

    bool isCyclic(auto &grid, auto &visited, auto &rec,auto &dir,int i, int j,int iP, int jP, char last) {
        visited[i][j] = true;
        rec[i][j] = true;
        //cout << i << "\t" <<  j <<  "\t" << grid[i][j] << "\n";
        for(auto &d: dir) {
            int x = i + d[0];
            int y = j + d[1];
            if(x == iP && y == jP)
                continue;
            if(isValid(x,y,grid,last) && !visited[x][y]) {
                if(isCyclic(grid,visited,rec,dir,x,y,i,j,last))
                    return true;
            }
            else if(isValid(x,y,grid,last) &&  rec[x][y]) {
                //cout << "Rec\t" << x <<"\t" << y <<"\n";
                return true;
            }
        }
        rec[i][j] = false;
        return false;
    }

    bool isValid(int x, int y, auto &grid, char last) {
        if(x <0 || y <0 || x >=grid.size() || y>=grid[0].size() || grid[x][y] != last)
            return false;
        return true;
    }
};
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