Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:37:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<G[nod].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:79:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<s[i].size();++j) ^ user.cpp:84:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<s[i].size();++j) ^ user.cpp:58:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.in","r",stdin); ^ user.cpp:59:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.out","w",stdout); ^ user.cpp:61:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:65:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &a, &b); ^