Compilare: main.cpp: In function 'void dfs(int)': main.cpp:18:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<vf[x].size(); ++i) ~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:25:31: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &n,&m); ^ main.cpp:30:35: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &x,&y); ^