Compilare: main.cpp: In function 'void solve()': main.cpp:74:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ans.size() != 2*n){ ~~~~~~~~~~~^~~~~~ main.cpp: In function 'int main()': main.cpp:86:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dungeon.in","r",stdin); ^ main.cpp:87:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dungeon.out","w",stdout); ^