Compilare: main.cpp: In function 'void dfs(int, int)': main.cpp:49:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<G[nod].size(); ++i) ~^~~~~~~~~~~~~~ main.cpp: In function 'void read(int&)': main.cpp:28:39: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(ch, 1, bsize, stdin); ^ main.cpp:41:39: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(ch, 1, bsize, stdin); ^ main.cpp: In function 'int main()': main.cpp:70:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pscnv.in", "r", stdin); ^ main.cpp:71:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pscnv.out", "w", stdout); ^ main.cpp:72:31: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(ch, 1, bsize, stdin); ^