二叉树

public class BinaryTreeDemo {

    public static void main(String[] args) {

        BinaryTree binaryTree = new BinaryTree();
        HeroNode root = new HeroNode(1, "宋江");
        HeroNode root2 = new HeroNode(2, "吴用");
        HeroNode root3 = new HeroNode(3, "卢俊义");
        HeroNode root4 = new HeroNode(4, "林冲");
        HeroNode root5 = new HeroNode(5, "关胜");
        //手动创树
        root.setLeft(root2);
        root.setRight(root3);
        root3.setRight(root4);
        root3.setLeft(root5);

        binaryTree.setRoot(root);

        System.out.println("前");
        binaryTree.preOrder();
        System.out.println("中");
        binaryTree.infixOrder();
        System.out.println("后");
        binaryTree.postOrder();

        HeroNode node = binaryTree.preOrderSearch(5);
        HeroNode node2 = binaryTree.infixOrderSearch(5);
        HeroNode node3 = binaryTree.postOrderSearch(5);
        System.out.println(node3);

        binaryTree.delNode(3);//附带后面删除
        binaryTree.del(3);//只删除本身
        System.out.println();
        binaryTree.preOrder();
    }

}

//定义二叉树
class BinaryTree {
    private HeroNode root;

    public void setRoot(HeroNode root) {
        this.root = root;
    }

    //前
    public void preOrder() {
        if (this.root != null) {
            this.root.preOrder();
        } else {
            System.out.println("null");
        }
    }

    //中
    public void infixOrder() {
        if (this.root != null) {
            this.root.infixOrder();
        } else {
            System.out.println("null");
        }
    }

    //后
    public void postOrder() {
        if (this.root != null) {
            this.root.postOrder();
        } else {
            System.out.println("null");
        }
    }

    //查找
    public HeroNode preOrderSearch(int no) {
        if (root != null) {
            return root.preOrderSearch(no);
        } else {
            return null;
        }
    }

    public HeroNode infixOrderSearch(int no) {
        if (root != null) {
            return root.infixOrderSearch(no);
        } else {
            return null;
        }
    }

    public HeroNode postOrderSearch(int no) {
        if (root != null) {
            return root.postOrderSearch(no);
        } else {
            return null;
        }
    }

    //删除
    public void delNode(int no) {
        if (root != null) {
            if (root.getNo() == no) {
                root = null;
            } else {
                root.delNode(no);
            }
        } else {
            System.out.println("空树");
        }
    }

    public void del(int no) {
        if (root != null) {
            if (root.getNo() == no) {
                root = null;
            } else {
                root.del(no);
            }
        } else {
            System.out.println("空树");
        }
    }

}

class HeroNode {
    private int no;
    private String name;
    private HeroNode left;
    private HeroNode right;

    public HeroNode(int no, String name) {
        this.no = no;
        this.name = name;
    }

    public int getNo() {
        return no;
    }

    public void setNo(int no) {
        this.no = no;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public HeroNode getLeft() {
        return left;
    }

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

    public HeroNode getRight() {
        return right;
    }

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

    @Override
    public String toString() {
        return "HeroNode[" +
                "no=" + no +
                ", name=‘" + name + ‘\‘‘ +
                ‘]‘;
    }

    /*
        是什么遍历看什么时候输出父节点
     */
    //前序遍历
    public void preOrder() {
        System.out.println(this);
        if (this.left != null) {
            this.left.preOrder();
        }
        if (this.right != null) {
            this.right.preOrder();
        }
    }

    //中序遍历
    public void infixOrder() {
        if (this.left != null) {
            this.left.infixOrder();
        }
        System.out.println(this);
        if (this.right != null) {
            this.right.infixOrder();
        }
    }

    //后续遍历
    public void postOrder() {
        if (this.left != null) {
            this.left.postOrder();
        }
        if (this.right != null) {
            this.right.postOrder();
        }
        System.out.println(this);
    }

    //前序查找
    public HeroNode preOrderSearch(int no) {
        if (this.no == no) {
            return this;
        }
        HeroNode resNode = null;
        if (this.left != null) {
            resNode = this.left.preOrderSearch(no);
        }
        if (resNode != null) {
            return resNode;
        }
        if (this.right != null) {
            resNode = this.right.preOrderSearch(no);
        }
        return resNode;
    }

    //中序查找
    public HeroNode infixOrderSearch(int no) {
        HeroNode resNode = null;
        if (this.left != null) {
            resNode = this.left.infixOrderSearch(no);
        }
        if (resNode != null) {
            return resNode;
        }
        if (this.no == no) {
            return this;
        }
        if (this.right != null) {
            resNode = this.right.infixOrderSearch(no);
        }
        return resNode;
    }

    //后序查找
    public HeroNode postOrderSearch(int no) {
        HeroNode resNode = null;
        if (this.left != null) {
            resNode = this.left.postOrderSearch(no);
        }
        if (resNode != null) {
            return resNode;
        }
        if (this.right != null) {
            resNode = this.right.postOrderSearch(no);
        }
        if (resNode != null) {
            return resNode;
        }
        if (this.no == no) {
            return this;
        }
        return resNode;
    }

    public void delNode(int no) {
        if (this.left != null && this.left.no == no) {
            this.left = null;
            return;
        }
        if (this.right != null && this.right.no == no) {
            this.right = null;
            return;
        }
        if (this.left != null) {
            this.left.delNode(no);
        }
        if (this.right != null) {
            this.right.delNode(no);
        }
    }

    public void del(int no) {
        if (this.left != null && this.left.no == no) {
            this.left = null;
            return;
        }
        if (this.right != null && this.right.no == no) {
            if (this.right.left != null && this.right.right != null) {
                this.right.left.right = this.right.right;
                this.right = this.right.left;
                return;
            } else {
                this.right = null;
                return;
            }
        }
        if (this.left != null) {
            this.left.delNode(no);
        }
        if (this.right != null) {
            this.right.delNode(no);
        }
    }
}