Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:30:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < g[n].size(); i++) ^ user.cpp:32:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < t[n].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:38:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.in", "r", stdin); ^ user.cpp:39:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.out", "w", stdout); ^ user.cpp:40:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:44:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^