Compilare: user.cpp: In function ‘void solve()’: user.cpp:52:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[s.x].size();++j) if(!viz[v[s.x][j]]) father = v[s.x][j]; ^ user.cpp:60:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[father].size();++i) if(viz[ v[father][i] ]) u.c += D[ v[father][i] ]; ^ user.cpp: In function ‘int main()’: user.cpp:75:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cezar.in", "r", stdin); ^ user.cpp:76:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cezar.out", "w", stdout); ^ user.cpp:80:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%hd %hd", &n,&k); ^ user.cpp:83:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%hd %hd", &a,&b); ^