Compilare: main.cpp: In function 'int bfs(int, int)': main.cpp:58:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<g[u].size(); i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:73:9: warning: variable 'n' set but not used [-Wunused-but-set-variable] int n,m,x,y,x1,y1,z,i; ^ main.cpp: In function 'char read_ch()': main.cpp:30:32: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(_in_buff, 1, 4096, fin); ^