Compilare: user.cpp: In function ‘void solve_queries()’: user.cpp:91:48: 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:117:33: 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:118:35: 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:119:17: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ch=0;gets(s); ^ user.cpp:123:21: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ch=0;gets(s); ^ user.cpp:129:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s);ch=0; ^ user.cpp:133:21: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ch=0;gets(s); ^ /tmp/ccB6pYai.o: In function `main': user.cpp:(.text.startup+0x60): warning: the `gets' function is dangerous and should not be used.