Compilare: user.cpp: In function ‘void dfst(int, int)’: user.cpp:18:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<b[x].size();i++) ^ user.cpp: In function ‘void dfs(int)’: user.cpp:26:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a[x].size();i++) ^ user.cpp: In function ‘int main()’: 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); ^ user.cpp:36:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&x,&y); ^