Compilare: user.cpp: In function ‘int dfs2(int)’: user.cpp:25:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<v[nod].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:59:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[nod].size();j++) ^ user.cpp:40:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hektor.in","r",stdin); ^ user.cpp:41:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld%ld%ld%ld",&n,&m,&a,&b); ^ user.cpp:43:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&cost[i]); ^ user.cpp:46:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld%ld",&x,&y); ^