// 547. Number of Provinces #include #include #include /* * dthere are 'n' cities. some of them are connected, while some are not. if * city 'a' is connected directly with city 'b', and city 'b' is connected * directly with city 'c', then city 'a' is connected indirectly with city 'c'. * a province is a group of directly or indirectly connected cities and no other * cities outside of the group. given an 'n x n' matrix 'is_connected' where * 'is_connected[i][j] = 1' if the i'th city and the j'th city are directly * connected, and 'is_connected[i][j] = 0' otherwise. return the total number of * provinces */ void dfs(int **is_connected, bool *vis, int n, int i) { for (int j = 0; j < n; j++) { if (is_connected[i][j] && !vis[j]) { is_connected[i][j] = 0; vis[j] = true; dfs(is_connected, vis, n, j); } } } int findCircleNum(int **is_connected, int is_connected_size, int *is_connected_col_size) { int ans = 0; bool *vis = calloc(is_connected_size, sizeof(bool)); for (int i = 0; i < is_connected_size; i++) { if (is_connected[i][i] && !vis[i]) { ans++; vis[i] = true; is_connected[i][i] = 0; dfs(is_connected, vis, is_connected_size, i); } } free(vis); return ans; } int main() { int ic1[3][3] = {{1, 1, 0}, {1, 1, 0}, {0, 0, 1}}, ics1 = 3, *iccs1; int ic2[3][3] = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}, ics2 = 3, *iccs2; printf("%d\n", findCircleNum(ic1, ics1, iccs1)); // expect: 2 printf("%d\n", findCircleNum(ic2, ics2, iccs2)); // expect: 3 }