leetcode

Solution to some Leetcode problems written in C++

git clone git://git.dimitrijedobrota.com/leetcode.git

1074.cpp (800B)

0 class Solution { 1 public: 2 int numSubmatrixSumTarget(vector<vector<int>> &matrix, int target) const { 3 const int n = size(matrix), m = size(matrix[0]); 4 5 for (int i = 0; i < n; i++) { 6 for (int j = 0, acc = 0; j < m; j++) { 7 matrix[i][j] = acc += matrix[i][j]; 8 } 9 } 10 11 unordered_map<int, int> um; 12 int res = 0; 13 14 for (int i = 0; i < m; i++) { 15 for (int j = i; j < m; j++) { 16 um = {{0, 1}}; 17 int crnt = 0; 18 for (int k = 0; k < n; k++) { 19 crnt += matrix[k][j] - (i > 0 ? matrix[k][i - 1] : 0); 20 res += um[crnt - target]; 21 um[crnt]++; 22 } 23 } 24 } 25 26 return res; 27 } 28 };