Compilare: user.cpp: In function ‘void dfs1(int)’: user.cpp:18:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[x].size(); i++) ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:26:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v2[x].size(); i++) ^ user.cpp: In function ‘void inv()’: user.cpp:33:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<v[i].size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:38:27: 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:41:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&qq,&qqq); ^