Compilare: main.cpp: In function 'int main()': main.cpp:54:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<ans.size();++i) ~^~~~~~~~~~~ main.cpp:33:29: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d",&n,&m); ^ main.cpp:36:33: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d",&x,&y); ^