Compilare: user.cpp: In function ‘int main()’: user.cpp:43:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<qs.size() && qs[i].s<=chunk; ++i) { ^ user.cpp:56:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(++i; i<qs.size() && qs[i].s==qs[i-1].s; ++i) { ^ user.cpp:75:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<qs.size(); ++i) ^ user.cpp:28:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mayonaka.in", "r", stdin); ^ user.cpp:29:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mayonaka.out", "w", stdout); ^ user.cpp:32:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:37:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&x,&y,&s,&w); ^