<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) {
        ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
        const short n = grid.size() - 1, m = grid.front().size() - 1;
        queue<pair<short, short>> q;
        for(short i = 0, N = n + 1, M = m + 1; i < N; i++) for(short j = 0; j < M; j++) q.push({i, j});
        while(!q.empty()){
            const short i = q.front().first, j = q.front().second;
            q.pop();
            if(i == -1 || j == -1 || i > n || j > m || grid[i][j] == '.') continue;
            char &c = grid[i][j];
            if(i > 0 && c == grid[i - 1][j]){
                if(i < n && grid[i + 1][j] == c){
                    continue;
                }else if(j > 0 && c == grid[i][j - 1]){
                    continue;
                }else if(j < m && c == grid[i][j + 1]){
                    continue;
                }else{
                    c = '.';
                    q.push({i + 1, j}), q.push({i - 1, j}), q.push({i, j - 1}), q.push({i, j + 1});
                }
            }else if(i < n && grid[i + 1][j] == c){
                if(j > 0 && c == grid[i][j - 1]){
                    continue;
                }else if(j < m && c == grid[i][j + 1]){
                    continue;
                }else{
                    c = '.';
                    q.push({i + 1, j}), q.push({i - 1, j}), q.push({i, j - 1}), q.push({i, j + 1});
                }
            }else if(j > 0 && c == grid[i][j - 1]){
                if(j < m && c == grid[i][j + 1]){
                    continue;
                }else{
                    c = '.';
                    q.push({i + 1, j}), q.push({i - 1, j}), q.push({i, j - 1}), q.push({i, j + 1});
                }
            }else{
                c = '.';
                q.push({i + 1, j}), q.push({i - 1, j}), q.push({i, j - 1}), q.push({i, j + 1});
            }
        }
        return grid != vector<vector<char>>(n + 1, vector<char>(m + 1, '.'));
    }
};
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