Compilare: user.cpp: In function ‘int main()’: user.cpp:51:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<a[1].size();i++) {d[a[1][i].first]=a[1][i].second;t[a[1][i].first]=1;} ^ user.cpp:47:25: 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:48:49: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i=1;i<=m;i++) {fscanf(f1,"%d%d%d",&u,&v,&c);a[u].push_back(make_pair(v,c));a[v].push_back(make_pair(u,c));} ^