Compilare: user.cpp: In function ‘void add_edges(int)’: user.cpp:33:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<g[x].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:42:15: warning: variable ‘f2’ set but not used [-Wunused-but-set-variable] FILE *f1,*f2; ^ user.cpp:46:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d%d",&n,&m); ^ user.cpp:49:40: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d%d%d",&x,&y,&cost); ^