Compilare: main.cpp: In function 'int main()': main.cpp:57:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans.size() == m + 1) { ~~~~~~~~~~~^~~~~~~~ main.cpp:18:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("domino.in", "r", stdin); ^ main.cpp:19:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("domino.out", "w", stdout); ^ main.cpp:22:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &m); ^ main.cpp:26:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &u, &v); ^