Compilare: user.cpp: In function ‘int main()’: user.cpp:45:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<sol.size();++j) ^ user.cpp:36:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d %d",&N,&M); ^ user.cpp:38:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d %d",&x,&y); ^