Compilare: user.cpp: In function ‘int main()’: user.cpp:24:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<v[x].size();i++){ ~^~~~~~~~~~~~ user.cpp:14:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d%d",&n,&m,&s); ^ user.cpp:16:33: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d",&x1,&x2); ^