Compilare: user.cpp: In function ‘int main()’: user.cpp:82:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<query.size();++j) ^ user.cpp:107:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<dq[i].size();++j) ^ user.cpp:30:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dir.in","r",stdin); ^ user.cpp:31:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dir.out","w",stdout); ^ user.cpp:33:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",str); ^