Compilare: user.cpp: In function ‘int main()’: user.cpp:33:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size(); ++j) ^ user.cpp:49:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size(); ++j) ^ user.cpp:66:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size(); ++j) ^ user.cpp:83:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<gx[val].size(); ++j) ^ user.cpp:14:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ograzi.in","r",stdin); ^ user.cpp:15:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ograzi.out","w",stdout); ^ user.cpp:17:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m,&w,&h); ^ user.cpp:20:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^ user.cpp:28:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^