Compilare: user.cpp: In function ‘void df(int*, int)’: user.cpp:35:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[x].size(); i++) { ^ user.cpp: In function ‘void dfsol(int)’: user.cpp:63:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < GM[x].size(); i++) { ^ user.cpp: In function ‘bool drum()’: user.cpp:87:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < GM[x].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:187:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ans.size(); i++) { ^ user.cpp:130:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("asfalt.in", "r", stdin); ^ user.cpp:131:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("asfalt.out", "w", stdout); ^ user.cpp:133:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d", &N, &M, &S, &D); ^ user.cpp:135:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &x, &y, &c); ^