Compilare: user.cpp: In function ‘int main()’: user.cpp:57:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<H[i].size();++j) ^ user.cpp:39:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rrmst.in","r",stdin); ^ user.cpp:40:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rrmst.out","w",stdout); ^ user.cpp:42:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i=1,scanf("%d",&N);i<=N;++i) ^ user.cpp:44:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&po[i].F,&po[i].S); ^