blackh

let silv n =
	let u = make_vect (2*n+1) 0 in
	let k = ref 2 in let j = ref 3 in let p = ref 3 in
		u.(1)<- 1; u.(2)<-2; u.(3)<-2;
		while u.(n)==0 do
			for i=1 to !k do u.(!p+i) <- !j; done;
			p:=!p+(!k); j:=!j+1; k:=u.(!j);
		done;
	u;;
	

blackh

let tri e =
let tmp = ref 0 in
if (e.(0)<e.(2)) then (tmp:=e.(0); e.(0)<-e.(2); e.(2) <- !tmp);
if (e.(1)<e.(0)) then (tmp:=e.(0); e.(0)<-e.(1); e.(1) <- !tmp);
if (e.(2)<e.(1)) then (tmp:=e.(1); e.(1)<-e.(2); e.(2) <- !tmp);
e;;

let echange i j v =
	let tmp = ref 0 in
	tmp:=v.(i); v.(i)<-v.(j); v.(j)<-(!tmp);