Compilare: user.cpp: In function ‘int readInt()’: user.cpp:19: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result user.cpp:24: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void read()’: user.cpp:31: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void dfs(int)’: user.cpp:45: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs2(int)’: user.cpp:60: warning: comparison between signed and unsigned integer expressions user.cpp:67: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void solve()’: user.cpp:96: warning: unused variable ‘nr’ user.cpp: In function ‘int main()’: user.cpp:126: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:127: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result