Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:19:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[x].size();i++){ ~^~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:32:21: warning: unused variable ‘j’ [-Wunused-variable] int x1,x2,n,m,i,j; ^ user.cpp:33:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d",&n,&m); ^ user.cpp:35:33: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d",&x1,&x2); ^