Compilare: user.cpp: In function ‘void read()’: user.cpp:15:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:20:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp: In function ‘void solve()’: user.cpp:34:24: warning: ‘nod’ may be used uninitialized in this function [-Wmaybe-uninitialized] vis[x] = vis[y] = 0; ^ user.cpp:73:13: note: ‘nod’ was declared here int nod; ^