<p>Given an <code>m x n</code> binary <code>matrix</code> filled with <code>0</code>&#39;s and <code>1</code>&#39;s, <em>find the largest square containing only</em> <code>1</code>&#39;s <em>and return its area</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/11/26/max1grid.jpg" style="width: 400px; height: 319px;" />
<pre>
<strong>Input:</strong> matrix = [[&quot;1&quot;,&quot;0&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;],[&quot;1&quot;,&quot;0&quot;,&quot;1&quot;,&quot;1&quot;,&quot;1&quot;],[&quot;1&quot;,&quot;1&quot;,&quot;1&quot;,&quot;1&quot;,&quot;1&quot;],[&quot;1&quot;,&quot;0&quot;,&quot;0&quot;,&quot;1&quot;,&quot;0&quot;]]
<strong>Output:</strong> 4
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/11/26/max2grid.jpg" style="width: 165px; height: 165px;" />
<pre>
<strong>Input:</strong> matrix = [[&quot;0&quot;,&quot;1&quot;],[&quot;1&quot;,&quot;0&quot;]]
<strong>Output:</strong> 1
</pre>

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

<pre>
<strong>Input:</strong> matrix = [[&quot;0&quot;]]
<strong>Output:</strong> 0
</pre>

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

<ul>
	<li><code>m == matrix.length</code></li>
	<li><code>n == matrix[i].length</code></li>
	<li><code>1 &lt;= m, n &lt;= 300</code></li>
	<li><code>matrix[i][j]</code> is <code>&#39;0&#39;</code> or <code>&#39;1&#39;</code>.</li>
</ul>

class Solution {
public:
    int solveWithMemo(int i,int j, vector<vector<char>>& mat,vector<vector<int>>& dp){
        int n=mat.size();
        int m=mat[0].size();
        if(i>=n || j>=m || mat[i][j]=='0') return 0;
        if(dp[i][j]!=-1) return dp[i][j];

        int d= solveWithMemo(i+1,j,mat,dp);
        int r= solveWithMemo(i,j+1,mat,dp);
        int rd= solveWithMemo(i+1,j+1,mat,dp);

        return dp[i][j]=1 + min({r,d,rd});
        
    }
    int maximalSquare(vector<vector<char>>& mat) {
        int n=mat.size();
        int m=mat[0].size();

        int c=0;
        vector<vector<int>> dp(n, vector<int>(m, -1));

        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(mat[i][j]=='1') c=max(c, solveWithMemo(i,j,mat,dp));
            }
        }
        return c*c;

    }
};
25000