Tree traversal: Difference between revisions
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→{{header|11l}}: Void
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Line 44:
.right = right
F preorder(visitor) ->
visitor(.data)
I .left != N
Line 51:
.right.preorder(visitor)
F inorder(visitor) ->
I .left != N
.left.inorder(visitor)
Line 58:
.right.inorder(visitor)
F postorder(visitor) ->
I .left != N
.left.postorder(visitor)
Line 65:
visitor(.data)
F preorder2(&d, level = 0) ->
d[level].append(.data)
I .left != N
Line 300:
queue: equ $ ; Put level-order queue on heap</syntaxhighlight>
{{out}}
<pre>Preorder: 1 2 4 7 5 3 6 8 9
Inorder: 7 4 2 5 1 8 6 9 3
Postorder: 7 4 5 2 8 9 6 3 1
Level-order: 1 2 3 4 5 6 7 8 9</pre>
=={{header|8086 Assembly}}==
<syntaxhighlight lang="nasm"> cpu 8086
org 100h
section .text
jmp demo
;;; Traverse tree at SI. Call routine at CX with values in AX.
;;; CX must preserve BX, CX, SI, DI.
;;; Preorder traversal
preo: test si,si
jz pdone ; Zero pointer = done
lodsw ; Load value
call cx ; Handle value
push si ; Keep value
mov si,[si] ; Load left node
call preo ; Traverse left node
pop si
mov si,[si+2] ; Load right node
jmp preo ; Traverse right node
;;; Inorder traversal
ino: test si,si
jz pdone ; Zero pointer = done
push si
mov si,[si+2] ; Load left node
call ino ; Traverse left node
pop si
lodsw ; Load value
call cx ; Handle value
mov si,[si+2] ; Load right node
jmp ino ; Traverse right node
;;; Postorder traversal
posto: test si,si
jz pdone ; Zero pointer = done
push si
mov si,[si+2] ; Load left node
call posto ; Traverse left node
pop si
push si
mov si,[si+4] ; Load right node
call posto
pop si ; Load value
lodsw
jmp cx ; Handle value
pdone: ret
;;; Level-order traversal
lvlo: mov di,queue ; DI = queue end pointer
mov ax,si
mov si,di ; SI = queue start pointer
stosw
.step: cmp di,si ; If end == start, done
je pdone
lodsw ; Get next item
test ax,ax ; Null?
jz .step
mov bx,si ; Keep start pointer in BX
mov si,ax ; Load item
lodsw ; Get value
call cx ; Handle value
lodsw ; Copy nodes to queue
stosw
lodsw
stosw
mov si,bx ; Put start pointer back
jmp .step
;;; Demo code
demo: mov si,orders
.loop: lodsw ; Load next order
test ax,ax
jz .done
mov dx,ax ; Print order name
mov ah,9
int 21h
lodsw ; Load order routine
mov bp,si ; Keep SI
mov si,tree ; Traverse the tree
mov cx,pdgt ; Printing the digits
call ax
mov si,bp
jmp .loop
.done: ret
;;; Callback: print single digit
pdgt: add al,'0'
mov [.str],al
mov ah,9
mov dx,.str
int 21h
ret
.str: db '* $'
section .data
;;; List of orders
orders: dw .preo,preo
dw .ino,ino
dw .posto,posto
dw .lvlo,lvlo
dw 0
.preo: db 'Preorder: $'
.ino: db 13,10,'Inorder: $'
.posto: db 13,10,'Postorder: $'
.lvlo: db 13,10,'Level-order: $'
;;; Exampe tree
tree: dw 1,.n2,.n3
.n2: dw 2,.n4,.n5
.n3: dw 3,.n6,0
.n4: dw 4,.n7,0
.n5: dw 5,0,0
.n6: dw 6,.n8,.n9
.n7: dw 7,0,0
.n8: dw 8,0,0
.n9: dw 9,0,0
section .bss
queue: resw 256</syntaxhighlight>
{{out}}
<pre>Preorder: 1 2 4 7 5 3 6 8 9
Line 3,791 ⟶ 3,912:
[7, 4, 2, 5, 1, 8, 6, 9, 3]
[7, 4, 5, 2, 8, 9, 6, 3, 1]</pre>
=={{header|Delphi}}==
{{works with|Delphi|6.0}}
{{libheader|SysUtils,StdCtrls}}
<syntaxhighlight lang="Delphi">
{Structure holding node data}
type PNode = ^TNode;
TNode = record
Data: integer;
Left,Right: PNode;
end;
function PreOrder(Node: TNode): string;
{Recursively traverse Node-Left-Right}
begin
Result:=IntToStr(Node.Data);
if Node.Left<>nil then Result:=Result+' '+PreOrder(Node.Left^);
if Node.Right<>nil then Result:=Result+' '+PreOrder(Node.Right^);
end;
function InOrder(Node: TNode): string;
{Recursively traverse Left-Node-Right}
begin
Result:='';
if Node.Left<>nil then Result:=Result+inOrder(Node.Left^);
Result:=Result+IntToStr(Node.Data)+' ';
if Node.Right<>nil then Result:=Result+inOrder(Node.Right^);
end;
function PostOrder(Node: TNode): string;
{Recursively traverse Left-Right-Node}
begin
Result:='';
if Node.Left<>nil then Result:=Result+PostOrder(Node.Left^);
if Node.Right<>nil then Result:=Result+PostOrder(Node.Right^);
Result:=Result+IntToStr(Node.Data)+' ';
end;
function LevelOrder(Node: TNode): string;
{Traverse the tree at each level, Left to right}
var Queue: TList;
var NT: TNode;
begin
Queue:=TList.Create;
try
Result:='';
Queue.Add(@Node);
while true do
begin
{Display oldest node in queue}
NT:=PNode(Queue[0])^;
Queue.Delete(0);
Result:=Result+IntToStr(NT.Data)+' ';
{Queue left and right children}
if NT.left<>nil then Queue.add(NT.left);
if NT.right<>nil then Queue.add(NT.right);
if Queue.Count<1 then break;
end;
finally Queue.Free; end;
end;
procedure ShowBinaryTree(Memo: TMemo);
var Tree: array [0..9] of TNode;
var I: integer;
begin
{Fill array of node with data}
{that matchs its position in the array}
for I:=0 to High(Tree) do
begin
Tree[I].Data:=I+1;
Tree[I].Left:=nil;
Tree[I].Right:=nil;
end;
{Build the specified tree}
Tree[0].left:=@Tree[2-1];
Tree[0].right:=@Tree[3-1];
Tree[1].left:=@Tree[4-1];
Tree[1].right:=@Tree[5-1];
Tree[3].left:=@Tree[7-1];
Tree[2].left:=@Tree[6-1];
Tree[5].left:=@Tree[8-1];
Tree[5].right:=@Tree[9-1];
{Tranverse the tree in four specified ways}
Memo.Lines.Add('Pre-Order: '+PreOrder(Tree[0]));
Memo.Lines.Add('In-Order: '+InOrder(Tree[0]));
Memo.Lines.Add('Post-Order: '+PostOrder(Tree[0]));
Memo.Lines.Add('Level-Order: '+LevelOrder(Tree[0]));
end;
</syntaxhighlight>
{{out}}
<pre>
Pre-Order: 1 2 4 7 5 3 6 8 9
In-Order: 7 4 2 5 1 8 6 9 3
Post-Order: 7 4 5 2 8 9 6 3 1
Level-Order: 1 2 3 4 5 6 7 8 9
Elapsed Time: 4.897 ms.
</pre>
=={{header|Draco}}==
Line 3,924 ⟶ 4,156:
levelOrder(btree, fn v { print(" ", v) })
println()</syntaxhighlight>
=={{header|EasyLang}}==
{{trans|C}}
<syntaxhighlight lang=easylang>
tree[] = [ 1 2 3 4 5 6 -1 7 -1 -1 -1 8 9 ]
#
proc preorder ind . .
if ind > len tree[] or tree[ind] = -1
return
.
write " " & tree[ind]
preorder ind * 2
preorder ind * 2 + 1
.
write "preorder:"
preorder 1
print ""
#
proc inorder ind . .
if ind > len tree[] or tree[ind] = -1
return
.
inorder ind * 2
write " " & tree[ind]
inorder ind * 2 + 1
.
write "inorder:"
inorder 1
print ""
#
proc postorder ind . .
if ind > len tree[] or tree[ind] = -1
return
.
postorder ind * 2
postorder ind * 2 + 1
write " " & tree[ind]
.
write "postorder:"
postorder 1
print ""
#
global tail head queue[] .
proc initqu n . .
len queue[] n
tail = 1
head = 1
.
proc enqu v . .
queue[tail] = v
tail = (tail + 1) mod1 len queue[]
.
func dequ .
if head = tail
return -1
.
h = head
head = (head + 1) mod1 len queue[]
return queue[h]
.
initqu len tree[]
proc levelorder n . .
enqu n
repeat
ind = dequ
until ind = -1
if ind < len tree[] and tree[ind] <> -1
write " " & tree[ind]
enqu ind * 2
enqu ind * 2 + 1
.
.
.
write "level-order:"
levelorder 1
print ""
</syntaxhighlight>
{{out}}
<pre>
preorder: 1 2 4 7 5 3 6 8 9
inorder: 7 4 2 5 1 8 6 9 3
postorder: 7 4 5 2 8 9 6 3 1
level-order: 1 2 3 4 5 6 7 8
</pre>
=={{header|Eiffel}}==
Line 4,109 ⟶ 4,425:
=={{header|Elena}}==
ELENA
<syntaxhighlight lang="elena">import extensions;
import extensions'routines;
Line 4,122 ⟶ 4,438:
class Node
{
constructor new(int value)
Line 4,188 ⟶ 4,504:
LevelOrder = new Enumerable
{
Queue<Node> queue := class Queue<Node>.allocate(4).push
Enumerator enumerator() = new Enumerator
Line 4,194 ⟶ 4,510:
bool next() = queue.isNotEmpty();
get Value()
{
Node item := queue.pop();
Line 5,165 ⟶ 5,481:
</pre>
=={{header|
{{FormulaeEntry|page=https://formulae.org/?script=examples/Tree_traversal}}
'''Solution'''
Notice that the action to do when visiting a node is provided as a lambda expression:
[[File:Fōrmulæ - Tree traversal 01.png]]
[[File:Fōrmulæ - Tree traversal 02.png]]
[[File:Fōrmulæ - Tree traversal 03.png]]
[[File:Fōrmulæ - Tree traversal 04.png]]
'''Test case for pre-order'''
[[File:Fōrmulæ - Tree traversal 05.png]]
[[File:Fōrmulæ - Tree traversal 06.png]]
'''Test case for in-order'''
[[File:Fōrmulæ - Tree traversal 07.png]]
[[File:Fōrmulæ - Tree traversal 08.png]]
'''Test case for post-order'''
[[File:Fōrmulæ - Tree traversal 09.png]]
[[File:Fōrmulæ - Tree traversal 10.png]]
'''Test case for breadth-first search'''
[[File:Fōrmulæ - Tree traversal 11.png]]
[[File:Fōrmulæ - Tree traversal 12.png]]
=={{header|GFA Basic}}==
Line 9,406 ⟶ 9,754:
level-order: 1 2 3 4 5 6 7 8 9
</pre>
=={{header|Refal}}==
<syntaxhighlight lang="refal">$ENTRY Go {
= <Show Preorder <Tree>>
<Show Inorder <Tree>>
<Show Postorder <Tree>>
<Show Levelorder <Tree>>;
};
Show {
s.F t.T = <Prout s.F ': ' <Mu s.F t.T>>;
};
Tree {
= (1 (2 (4 (7 () ()) ()) (5 () ())) (3 (6 (8 () ()) (9 () ())) ()));
};
Preorder {
() = ;
(s.V t.L t.R) = s.V <Preorder t.L> <Preorder t.R>;
};
Inorder {
() = ;
(s.V t.L t.R) = <Inorder t.L> s.V <Inorder t.R>;
};
Postorder {
() = ;
(s.V t.L t.R) = <Postorder t.L> <Postorder t.R> s.V;
};
Levelorder {
= ;
() e.Q = <Levelorder e.Q>;
(s.V t.L t.R) e.Q = s.V <Levelorder e.Q t.L t.R>;
};</syntaxhighlight>
{{out}}
<pre>Preorder : 1 2 4 7 5 3 6 8 9
Inorder : 7 4 2 5 1 8 6 9 3
Postorder : 7 4 5 2 8 9 6 3 1
Levelorder : 1 2 3 4 5 6 7 8 9</pre>
=={{header|REXX}}==
Line 10,162 ⟶ 10,552:
level-order: [1,2,3,4,5,6,7,8,9]
</pre>
=={{header|SETL}}==
<syntaxhighlight lang="setl">program tree_traversal;
tree := [1, [2, [4, [7]], [5]], [3, [6, [8], [9]]]];
print("preorder ", preorder(tree));
print("inorder ", inorder(tree));
print("postorder ", postorder(tree));
print("level-order ", levelorder(tree));
proc preorder(tree);
if tree = om then return []; end if;
[item, left, right] := tree;
return [item] + preorder(left) + preorder(right);
end proc;
proc inorder(tree);
if tree = om then return []; end if;
[item, left, right] := tree;
return inorder(left) + [item] + inorder(right);
end proc;
proc postorder(tree);
if tree = om then return []; end if;
[item, left, right] := tree;
return postorder(left) + postorder(right) + [item];
end proc;
proc levelorder(tree);
items := [];
loop init queue := [tree]; while queue /= [] do
[item, left, right] fromb queue;
items with:= item;
if left /= om then queue with:= left; end if;
if right /= om then queue with:= right; end if;
end loop;
return items;
end proc;
end program;</syntaxhighlight>
{{out}}
<pre>preorder [1 2 4 7 5 3 6 8 9]
inorder [7 4 2 5 1 8 6 9 3]
postorder [7 4 5 2 8 9 6 3 1]
level-order [1 2 3 4 5 6 7 8 9]</pre>
=={{header|Sidef}}==
Line 10,819 ⟶ 11,253:
{{trans|Kotlin}}
The object-oriented version.
<syntaxhighlight lang="
construct new(v) {
_v = v
|