Number of Submatrices That Sum to Target LeetCode solution in C++

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class Solution {
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 public:
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  int numSubmatrixSumTarget(vector<vector<int>> &matrix, int target) {
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    int n = matrix.size(), m = matrix[0].size(), count = 0;
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    vector<vector<int>> temp(n + 1, vector<int>(m));
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    for (int i = 0; i < n; i++) {
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      for (int j = 0; j < m; j++) {
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        temp[i + 1][j] = temp[i][j] + matrix[i][j];
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      }
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    }
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    for (int i = 0; i < n; i++) {
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      for (int j = i + 1; j <= n; j++) {
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        for (int k = 0; k < m; k++) {
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          int sum = 0;
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          for (int l = k; l < m; l++) {
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            sum += temp[j][l] - temp[i][l];
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            if (sum == target) {
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              // cout<<j<<" "<<i<<" "<<k<<endl;
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              count++;
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            }
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          }
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        }
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      }
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    }
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    return count;
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  }
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};