Compilare: user.cpp: In function ‘void solve_queries()’: user.cpp:93:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<v[fix][ind].size();j++) ^ user.cpp: In function ‘int main()’: user.cpp:114:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tri2.in","r",stdin); ^ user.cpp:115:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tri2.out","w",stdout); ^ user.cpp:116:17: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ch=0;gets(s); ^ user.cpp:120:21: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ch=0;gets(s); ^ user.cpp:126:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s);ch=0; ^ user.cpp:130:21: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ch=0;gets(s); ^ /tmp/cc81VJxm.o: In function `main': user.cpp:(.text.startup+0x60): warning: the `gets' function is dangerous and should not be used.