Compilare: user.cpp: In function ‘void write()’: user.cpp:48:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < H[i].size(); ++ j) ^ user.cpp: In function ‘void read()’: user.cpp:20:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &t, &n); ^ user.cpp:21:24: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(a, 13, stdin); ^ user.cpp: In function ‘void solve()’: user.cpp:31:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s\n", s[i]); ^