Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:17:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<v[x].size(); i++) ^ user.cpp:20:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<from[x].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:29:24: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d",&n); ^ user.cpp:33:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d",&a[i][j]); ^