Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:21:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(mx < fr[it].size()) { ~~~^~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:48:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&n,&k); ^ user.cpp:51:35: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&x,&y); ^ user.cpp:56:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d " ,&col[i]); ^