跟郭峰争论遍历二叉树后

和郭峰争论遍历二叉树后

class Node{private String name;private Node leftChild;private Node rightChild;public Node(String name){this.name = name;}public void output(){System.out.print(name + "-->");}public Node getLeft(){return leftChild;}public void setLeft(Node leftChild){this.leftChild = leftChild;}public Node getRight(){return rightChild;}public void setRight(Node rightChild){this.rightChild = rightChild;}public String getName(){return name;}}

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BinaryTree.java

class BinaryTree{private Node root;private static Node pp;public Node getRoot(){return root;}private boolean iterateCompare(Node p, String name){// 插入节点前先遍历一下二叉树查看有没有该父节点if (p.getLeft() != null && iterateCompare(p.getLeft(), name)){return true;}if (p.getName().equals(name)){BinaryTree.pp = p;return true;}if (p.getRight() != null && iterateCompare(p.getRight(), name)){return true;}return false;}// 中序遍历输出public void inOrderIterateOutput(Node p){if (p.getLeft() != null){inOrderIterateOutput(p.getLeft());}p.output();if (p.getRight() != null){inOrderIterateOutput(p.getRight());}}// 先序遍历输出public void preOrderIterateOutput(Node p){p.output();if (p.getLeft() != null){preOrderIterateOutput(p.getLeft());}if (p.getRight() != null){preOrderIterateOutput(p.getRight());}}// 后序遍历输出public void postOrderIterateOutput(Node p){if (p.getLeft() != null){postOrderIterateOutput(p.getLeft());}if (p.getRight() != null){postOrderIterateOutput(p.getRight());}p.output();}public void initialize(){root = new Node("root");}public boolean addNode(String parent, String flag, String name){if (!(flag.equals("L") || flag.equals("R"))){return false;}if (iterateCompare(root, parent)){// 找到有该节点if (flag.equals("L") && BinaryTree.pp.getLeft() == null){BinaryTree.pp.setLeft(new Node(name));return true;}else if (flag.equals("R") && BinaryTree.pp.getRight() == null){BinaryTree.pp.setRight(new Node(name));return true;}else{return false;}}else{return false;}}}

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?Test.java

class Test{public static void main(String[] args){BinaryTree bt = new BinaryTree();bt.initialize();if (bt.addNode("root", "L", "A")){System.out.println("添加root--L-->A成功");}if (bt.addNode("root", "R", "B")){System.out.println("添加root--R-->B成功");}if (bt.addNode("A", "L", "C")){System.out.println("添加A--L-->C成功");}if (bt.addNode("B", "L", "D")){System.out.println("添加B--L-->D成功");}if (bt.addNode("B", "R", "E")){System.out.println("添加B--R-->E成功");}System.out.println("中序遍历");bt.inOrderIterateOutput(bt.getRoot());System.out.println("\n先序遍历");bt.preOrderIterateOutput(bt.getRoot());System.out.println("\n后序遍历");bt.postOrderIterateOutput(bt.getRoot());}}

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输出结果：

添加root--L-->A成功

添加root--R-->B成功

添加A--L-->C成功

添加B--L-->D成功

添加B--R-->E成功

中序遍历

C-->A-->root-->D-->B-->E-->

先序遍历

root-->A-->C-->B-->D-->E-->

后序遍历

C-->A-->D-->E-->B-->root-->

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