Compilare: main.cpp: In function 'void dfs(int, int)': main.cpp:52:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a[x].size();i++) ~^~~~~~~~~~~~ main.cpp: In function 'void read(int&)': main.cpp:13:39: 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, dim, stdin), pos = 0; ^ main.cpp:18:39: 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, dim, stdin), pos = 0; ^ main.cpp:23:39: 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, dim, stdin), pos = 0; ^ main.cpp: In function 'int main()': main.cpp:80:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arb.in", "r", stdin); ^ main.cpp:81:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("arb.out", "w", stdout); ^