Compilare: user.c: In function ‘M’: user.c:25:58: warning: operation on ‘h[l]’ may be undefined [-Wsequence-point] void M(int l,int k) { for(d[h[l]]=k;l>1&&d[h[l/2]]>k;h[l]^=h[l/2]^=h[l]^=h[l/2],w[h[l]]=l,w[h[l/2]]=l/2,l/=2); } ^ user.c: In function ‘main’: user.c:27:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in","r",stdin),freopen("apm.out","w",stdout),scanf("%d%d",&n,&m); ^ user.c:27:37: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in","r",stdin),freopen("apm.out","w",stdout),scanf("%d%d",&n,&m); ^ user.c:27:65: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in","r",stdin),freopen("apm.out","w",stdout),scanf("%d%d",&n,&m); ^ user.c:29:11: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&a[i],&b[i],&c[i]),u[a[i]]++,u[b[i]]++; ^