二叉树的遍历

节点代码

public class Node {

    private Node left;
    private Node right;
    private int value;

    public Node(int value) {
        this.value = value;
    }

    @Override
    public String toString() {
        return "Node{" +
                "value=" + value +
                '}';
    }

    public int getValue() {
        return value;
    }

    public Node getLeft() {
        return left;
    }

    public void setLeft(Node left) {
        this.left = left;
    }

    public Node getRight() {
        return right;
    }

    public void setRight(Node right) {
        this.right = right;
    }

}

树代码

public class BinaryTree {
    private Node root;

    public BinaryTree(Node root) {
        this.root = root;
    }

    public void preOrder(){
        preOrder(root);
    }

    public void midOrder(){
        midOrder(root);
    }

    public void postOrder(){
        postOrder(root);
    }

    /**
     * 前序遍历
     */
    private void preOrder(Node node){
        if (node==null) {
            return;
        }
        System.out.println(node.getValue());
        preOrder(node.getLeft());
        preOrder(node.getRight());

    }
    
    /**
     * 中序遍历
     */
    private void midOrder(Node node){
        if (node==null) {
            return;
        }
        midOrder(node.getLeft());
        System.out.println(node.getValue());
        midOrder(node.getRight());
    }
    
    /**
     * 后序遍历
     */
    private void postOrder(Node node){
        if (node==null) {
            return;
        }
        postOrder(node.getLeft());
        postOrder(node.getRight());
        System.out.println(node.getValue());
    }

}

测试代码

public class Test {
    public static void main(String[] args) {
        testBinaryTree();
    }

    private static void testBinaryTree() {
        Node node1 = new Node(1);
        Node node2 = new Node(2);
        Node node3 = new Node(3);
        Node node4 = new Node(4);
        Node node5 = new Node(5);
        Node node6 = new Node(6);
        Node node7 = new Node(7);
        node1.setLeft(node2);
        node1.setRight(node3);
        node2.setLeft(node4);
        node2.setRight(node5);
        node3.setLeft(node6);
        node3.setRight(node7);
        BinaryTree binaryTree = new BinaryTree(node1);
        binaryTree.preOrder();//前序遍历 1245367
        binaryTree.midOrder();//中序遍历 4251637
        binaryTree.postOrder();//后序遍历 4526731
    }
}