<p>There is an <code>m x n</code> grid with a ball. The ball is initially at the position <code>[startRow, startColumn]</code>. You are allowed to move the ball to one of the four adjacent cells in the grid (possibly out of the grid crossing the grid boundary). You can apply <strong>at most</strong> <code>maxMove</code> moves to the ball.</p>

<p>Given the five integers <code>m</code>, <code>n</code>, <code>maxMove</code>, <code>startRow</code>, <code>startColumn</code>, return the number of paths to move the ball out of the grid boundary. Since the answer can be very large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/04/28/out_of_boundary_paths_1.png" style="width: 500px; height: 296px;" />
<pre>
<strong>Input:</strong> m = 2, n = 2, maxMove = 2, startRow = 0, startColumn = 0
<strong>Output:</strong> 6
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/04/28/out_of_boundary_paths_2.png" style="width: 500px; height: 293px;" />
<pre>
<strong>Input:</strong> m = 1, n = 3, maxMove = 3, startRow = 0, startColumn = 1
<strong>Output:</strong> 12
</pre>

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

<ul>
	<li><code>1 &lt;= m, n &lt;= 50</code></li>
	<li><code>0 &lt;= maxMove &lt;= 50</code></li>
	<li><code>0 &lt;= startRow &lt; m</code></li>
	<li><code>0 &lt;= startColumn &lt; n</code></li>
</ul>

class Solution {
public:
    long long dp[51][51][51];
    long long solve(int i, int j, int m, int n, int maxMove)
    {
        if(maxMove < 0) return 0;
        if(i == m || j == n || i < 0 || j < 0) return 1;
        
        if(dp[i][j][maxMove] != -1) return dp[i][j][maxMove];
        
        long long a = solve(i+1, j, m, n, maxMove-1);
        long long b = solve(i-1, j, m, n, maxMove-1);
        long long c = solve(i, j+1, m, n, maxMove-1);
        long long d = solve(i, j-1, m, n, maxMove-1);
        
        return dp[i][j][maxMove] =  (a + b + c + d) % 1000000007; 
    }
    int findPaths(int m, int n, int maxMove, int startRow, int startColumn) 
    {
        memset(dp, -1, sizeof(dp));
        return solve(startRow, startColumn, m, n, maxMove);    
    }
};
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