Compilare: user.cpp: In function ‘int main()’: user.cpp:33:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<f[i].size();j++) ^ user.cpp:19:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(IN,"%d%d",&N,&K); ^ user.cpp:26:46: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(IN,"%d%d%d%d",&X1,&Y1,&X2,&Y2); ^