Compilare: user.cpp: In function ‘int dfs(int, int)’: user.cpp:49:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int it = 0;it < g[node].size();it++) ^ user.cpp:58:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int it = 0;it < v.size();it++) ^ user.cpp: In function ‘void read(int&)’: user.cpp:24:42: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff,1,Mn,stdin),pos = 0; ^ user.cpp:32:42: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff,1,Mn,stdin),pos = 0; ^ user.cpp: In function ‘int main()’: user.cpp:66:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zvon.in","r",stdin); ^ user.cpp:67:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zvon.out","w",stdout); ^