<p>Given a <code>matrix</code>&nbsp;and a <code>target</code>, return the number of non-empty submatrices that sum to <font face="monospace">target</font>.</p>

<p>A submatrix <code>x1, y1, x2, y2</code> is the set of all cells <code>matrix[x][y]</code> with <code>x1 &lt;= x &lt;= x2</code> and <code>y1 &lt;= y &lt;= y2</code>.</p>

<p>Two submatrices <code>(x1, y1, x2, y2)</code> and <code>(x1&#39;, y1&#39;, x2&#39;, y2&#39;)</code> are different if they have some coordinate&nbsp;that is different: for example, if <code>x1 != x1&#39;</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/09/02/mate1.jpg" style="width: 242px; height: 242px;" />
<pre>
<strong>Input:</strong> matrix = [[0,1,0],[1,1,1],[0,1,0]], target = 0
<strong>Output:</strong> 4
<strong>Explanation:</strong> The four 1x1 submatrices that only contain 0.
</pre>

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

<pre>
<strong>Input:</strong> matrix = [[1,-1],[-1,1]], target = 0
<strong>Output:</strong> 5
<strong>Explanation:</strong> The two 1x2 submatrices, plus the two 2x1 submatrices, plus the 2x2 submatrix.
</pre>

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

<pre>
<strong>Input:</strong> matrix = [[904]], target = 0
<strong>Output:</strong> 0
</pre>

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

<ul>
	<li><code>1 &lt;= matrix.length &lt;= 100</code></li>
	<li><code>1 &lt;= matrix[0].length &lt;= 100</code></li>
	<li><code>-1000 &lt;= matrix[i][j] &lt;= 1000</code></li>
	<li><code>-10^8 &lt;= target &lt;= 10^8</code></li>
</ul>

class Solution {
    public:
        int numSubmatrixSumTarget(vector<vector<int>>& matrix, int target) {
                int m = matrix.size(), n = matrix[0].size(), res = 0;

                        for (int l = 0; l < n; ++l) {
                                    int sums[105] = {0};
                                                for (int r = l; r < n; ++r) {
                                                                for (int i = 0; i < m; ++i) {
                                                                                    sums[i] += matrix[i][r];
                                                                                                    }
                                                                                                                    for (int i = 0; i < m; ++i) {
                                                                                                                                        int sum = 0;
                                                                                                                                                            for (int j = i; j < m; ++j) {
                                                                                                                                                                                    sum += sums[j];
                                                                                                                                                                                                            if (sum == target) {
                                                                                                                                                                                                                                        ++res;
                                                                                                                                                                                                                                                                }
                                                                                                                                                                                                                                                                                    }
                                                                                                                                                                                                                                                                                                    }
                                                                                                                                                                                                                                                                                                                }
                                                                                                                                                                                                                                                                                                                        }

                                                                                                                                                                                                                                                                                                                                return res;
                                                                                                                                                                                                                                                                                                                                    }
                                                                                                                                                                                                                                                                                                                                    };

13085