Compilare: user.cpp: In function ‘void Read()’: user.cpp:25: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void DFS(int, int)’: user.cpp:39: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void DFS2(int, int)’: user.cpp:51: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void Solve()’: user.cpp:61: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result