Java implementation two fork tree traversal

Reference: http://blog.csdn.net/wuwenxiang91322/article/details/12231657

Environment:

java:jdk1.8.0_91

ImportJava.util.Stack; Public classBinarytreetest {/*** The tree structure is as follows: * Root */* A B */\ * C D G */// * E F H I **/     Public Static voidMain (string[] args) {Node root=NewNode ("root"); Node A=NewNode ("A"), B =NewNode ("B"), C =NewNode ("C"), D =NewNode ("D"), E =NewNode ("E"), F=NewNode ("F"), G =NewNode ("G"), H =NewNode ("H"), I =NewNode ("I");        Root.setleft (A);        A.setleft (C);        A.setright (D);        C.setleft (E);        D.setleft (F);        Root.setright (B);        B.setright (G);        G.setleft (H);                G.setright (I); Binarytreetraversalor Tree=Binarytreetraversalor.pre_order; System.out.print (String.Format ("%s->", Tree.getstrategy ()));        Tree.execute (root); Tree=Binarytreetraversalor.in_order; System.out.print (String.Format ("\n%s->", Tree.getstrategy ()));        Tree.execute (root); Tree=Binarytreetraversalor.post_order; System.out.print (String.Format ("\n%s->", Tree.getstrategy ()));        Tree.execute (root); Tree=Binarytreetraversalor.pre_order_norecu; System.out.print (String.Format ("\n%s->", Tree.getstrategy ()));        Tree.execute (root); Tree=Binarytreetraversalor.in_order_norecu; System.out.print (String.Format ("\n%s->", Tree.getstrategy ()));        Tree.execute (root); Tree=Binarytreetraversalor.post_order_norecu; System.out.print (String.Format ("\n%s->", Tree.getstrategy ()));    Tree.execute (root); }}classNode {PrivateString value; PrivateNode left; PrivateNode right;  PublicNode (String value) { This. Value =value; }     PublicString GetValue () {returnvalue; }     PublicNode GetLeft () {returnLeft ; }     Public voidSetleft (Node left) { This. left =Left ; }     PublicNode getRight () {returnRight ; }     Public voidSetright (Node right) { This. right =Right ; }}enumBinarytreetraversalor {in_order (Recursive in-sequence traversal) {@Override Public voidExecute (Node node) {if(Node! =NULL) {Execute (node.getleft ());                Visit (node);            Execute (node.getright ()); }}, Pre_order ("Recursive first-order traversal") {@Override Public voidExecute (Node node) {if(Node! =NULL) {Visit (node);                Execute (node.getleft ());            Execute (node.getright ()); }}, Post_order ("Recursive sequential Traversal") {@Override Public voidExecute (Node node) {if(Node! =NULL) {Execute (node.getleft ());                Execute (node.getright ());            Visit (node); }}, In_order_norecu ("Non-recursive in-sequence traversal") {@Override Public voidExecute (Node node) {Finalstack<node> stack =NewStack<>();  while(Node! =NULL|| !Stack.isempty ()) {                 while(Node! =NULL) {Stack.push (node); Node=Node.getleft (); }                if(Stack.size () > 0) {node=Stack.pop ();                    Visit (node); Node=node.getright (); }}}, Pre_order_norecu ("Non-recursive first-order traversal") {@Override Public voidExecute (Node node) {Finalstack<node> stack =NewStack<>();  while(Node! =NULL|| !Stack.isempty ()) {                 while(Node! =NULL) {Visit (node);                    Stack.push (node); Node=Node.getleft (); }                if(Stack.size () > 0) {node=Stack.pop (); Node=node.getright (); }}}, Post_order_norecu ("Non-recursive post-traversal") {//need to focus on understanding@Override Public voidExecute (Node node) {Finalstack<node> stack =NewStack<>(); Node tmp=NULL;  while(Node! =NULL) {                 while(Node.getleft ()! =NULL) {Stack.push (node); Node=Node.getleft (); }                 while(Node! =NULL&& (node.getright () = =NULL|| Node.getright () = = tmp)) {//The current node has no right subtree or right subtree output.Visit (node); //record last output nodeTMP =node; if(Stack.empty ())return; Node=Stack.pop ();                } stack.push (node); Node=node.getright ();    }        }    }; Private Static voidvisit (Node root) {System.out.print (Root.getvalue ()+ "\ T"); }    PrivateString strategy; Binarytreetraversalor (String strategy) { This. Strategy =strategy; }     Public Abstract voidExecute (node node);  PublicString getstrategy () {returnstrategy; }}

Java implementation two fork tree traversal