Compilare: user.cpp: In function ‘int main()’: user.cpp:84:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<ctc[i].size(); j++) ^ user.cpp: In function ‘void read()’: user.cpp:20:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:25:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^