Compilare: user.cpp: In function ‘long long int bfs(int)’: user.cpp:27: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:50: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:61: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result