Compilare: user.cpp: In function ‘int main()’: user.cpp:227:59: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (bfs(*AdjCol[c].begin()) == white.size()) ^ user.cpp:121:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unlock.in", "r", stdin); ^ user.cpp:122:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("unlock.out", "w", stdout); ^ user.cpp: In function ‘char getChar()’: user.cpp:15:45: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, BUFFER_SIZE, 1, stdin); ^