Compilare: user.cpp: In function ‘bool ok(int, int)’: user.cpp:21:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<check[nod].size()&&check[nod][i]!=x) ^ user.cpp:23:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return i==check[nod].size(); ^ user.cpp: In function ‘int main()’: user.cpp:60:31: 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:62:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&x,&y); ^