Compilare: user.cpp: In function ‘void solve_queries()’: user.cpp:100:48: 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:118:33: 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:119:35: 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:120:17: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ch=0;gets(s); ^ user.cpp:124:21: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ch=0;gets(s); ^ user.cpp:130:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s);ch=0; ^ user.cpp:134:21: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] ch=0;gets(s); ^ /tmp/ccHc1zNp.o: In function `main': user.cpp:(.text.startup+0x5e): warning: the `gets' function is dangerous and should not be used.