Compilare: main.cpp: In function 'void dfs(int)': main.cpp:59:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i<v[r].size(); i++) ~^~~~~~~~~~~~ main.cpp: In function 'char next()': main.cpp:19:35: 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, bsize, fin); ^