leetcode

Solution to some Leetcode problems written in C++

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

1284.cpp (1163B)

0 class Solution { 1 public: 2 int minFlips(const vector<vector<int>> &mat) const { 3 static const int offset[] = {-1, 0, 1, 0, -1}; 4 const int n = size(mat), m = size(mat[0]); 5 unsigned res = -1; 6 7 const auto valid = [&](int x, int y) { return x >= 0 && x < n && y >= 0 && y < m; }; 8 9 for (unsigned mask = 0; mask < 1 << (n * m); mask++) { 10 auto grid = mat; 11 12 for (unsigned k = 0, crnt = mask; crnt; crnt >>= 1, k++) { 13 if (!(crnt & 1)) continue; 14 15 const int a = k / m, b = k % m; 16 for (int k = 0; k < 4; k++) { 17 const int x = a + offset[k + 1]; 18 const int y = b + offset[k]; 19 20 if (!valid(x, y)) continue; 21 grid[x][y] = !grid[x][y]; 22 } 23 grid[a][b] = !grid[a][b]; 24 } 25 26 for (int i = 0; i < n; i++) { 27 for (int j = 0; j < m; j++) { 28 if (grid[i][j]) goto next; 29 } 30 } 31 32 res = min(res, (unsigned)popcount(mask)); 33 next:; 34 } 35 36 return res; 37 } 38 };