Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:20:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<graph[i].size();++i) ~^~~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:34:8: warning: unused variable ‘x’ [-Wunused-variable] int x,y; ^ user.cpp:34:10: warning: unused variable ‘y’ [-Wunused-variable] int x,y; ^ user.cpp:33:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&n,&m); ^