Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:13:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (register int i=0;i<L[nod].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:26:18: warning: unused variable ‘a’ [-Wunused-variable] register int a, c; ^ user.cpp:26:21: warning: unused variable ‘c’ [-Wunused-variable] register int a, c; ^ user.cpp:30:32: 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:38:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d", &v[1]); ^ user.cpp:41:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d", &v[i]); ^