Compilare: user.cpp: In function ‘void dfs_time(int)’: user.cpp:50: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs(int)’: user.cpp:72: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void read_and_solve()’: user.cpp:92: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:95: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:97: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘int main()’: user.cpp:111: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:112: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result