二叉樹排序在Java代碼的簡單實現

二叉樹排序在Java代碼的簡單實現

public class Main2Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        SortTree tree = new SortTree(10); // 初始化一個root並且給一個value
        tree.add(60);
        tree.add(15);
        tree.add(22);
        tree.add(17);
        tree.add(7);
        tree.add(8);
        tree.add(4);
        tree.add(13);

        tree.read();
        System.out.println("--root.value = " + tree.getRoot().getValue());
        tree.delete(12);
        System.out.println("---------after delete---------");
        tree.read();
        System.out.println("root.value = " + tree.getRoot().getValue());
    }


    class SortTree {
        private Node root;
        private int size;

        public SortTree(int v) {
            root = new Node(v);
            size = 1;
        }

        public Node getRoot() {
            return root;
        }

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

        public int Size() {
            return size;
        }

        public void add(int value) {
            if (root == null)
                return;
            Node indexRoot = getRoot();
            Node parent = indexRoot;
            int indexValue = 0;
            while (indexRoot != null) {
                indexValue = indexRoot.getValue();
                parent = indexRoot;
                if (value < indexValue) {
                    indexRoot = indexRoot.getLeft();
                } else if (value > indexValue) {
                    indexRoot = indexRoot.getRight();
                } else {
                    return;
                }
            }
            Node newNode = new Node(value);
            if (value < indexValue) {
                parent.setLeft(newNode);
            } else if (value > indexValue) {
                parent.setRight(newNode);
            } else {
                return;
            }
            newNode.setParent(parent);
            size++;
        }

        public void read() { // 中序遍歷
            read(root);
        }

        public void read(Node node) {
            if (node.getLeft() != null) {
                read(node.getLeft());
            }
            if (node != null) {
                System.out.println(node.getValue());
            }
            if (node.getRight() != null) {
                read(node.getRight());
            }
        }

        public void delete(int value) {
            if (root == null)
                return;
            Node indexRoot = getRoot();
            Node parent = indexRoot;
            int indexValue = indexRoot.getValue();
            while (indexValue != value && indexRoot != null) {
                parent = indexRoot;
                if (value < indexValue) {
                    indexRoot = indexRoot.getLeft();
                } else if (value > indexValue) {
                    indexRoot = indexRoot.getRight();
                }
                if (indexRoot != null) {
                    indexValue = indexRoot.getValue();
                }
            }

            if (indexRoot == null) {
                return;
            }

            // no any nodes
            if (indexRoot.getLeft() == null && indexRoot.getRight() == null) {
                if (parent.getLeft() == indexRoot) { // if is leftNode
                    parent.setLeft(null);
                } else { // if is rightNode
                    parent.setRight(null);
                }
                return;
            }

            // has only left node
            if (indexRoot.getLeft() != null && indexRoot.getRight() == null) {
                if (indexRoot == this.getRoot()) { // if deleted is root
                    setRoot(indexRoot.getLeft());
                    indexRoot = null;
                } else {
                    parent.setLeft(indexRoot.getLeft());
                    indexRoot.getLeft().setParent(parent);
                    indexRoot = null;
                }
                return;
            }

            // has only right node
            if (indexRoot.getLeft() == null && indexRoot.getRight() != null) {
                if (indexRoot == this.getRoot()) { // if deleted is root
                    setRoot(indexRoot.getRight());
                    indexRoot = null;
                } else {
                    parent.setRight(indexRoot.getRight());
                    indexRoot.getRight().setParent(parent);
                    indexRoot = null;
                }
                return;
            }

            // has two node
            if (indexRoot.getLeft() != null && indexRoot.getRight() != null) {

                // 找到刪除節點的後繼節點
                Node afterNode = indexRoot.getRight();
                Node afterFather = indexRoot;
                while (afterNode.getLeft() != null) {
                    afterFather = afterNode;
                    afterNode = afterNode.getLeft();
                }

                if (afterFather == indexRoot) {
                    parent.setRight(afterNode);
                    afterNode.setParent(parent);
                    afterNode.setLeft(indexRoot.getLeft());
                    indexRoot.getLeft().setParent(afterNode);
                    if (indexRoot == this.getRoot()) { //if delete is root
                        setRoot(afterNode);
                    }

                } else {
                    //比較複雜
                    if (afterNode.getRight() != null) {
                        afterFather.setLeft(afterNode.getRight());
                        afterNode.getRight().setParent(afterFather);
                    } else {
                        afterFather.setLeft(null);
                    }
                    afterNode.setRight(indexRoot.getRight());
                    indexRoot.getRight().setParent(afterNode);
                    parent.setRight(afterNode);
                    afterNode.setParent(parent);
                    afterNode.setLeft(indexRoot.getLeft());
                    indexRoot.getLeft().setParent(afterNode);
                    if (indexRoot == this.getRoot()) {
                        this.setRoot(afterNode);
                    }
                }
                indexRoot = null;
            }
        }
    }

    public class Node {
        private Node left;
        private Node right;
        private int value;
        private Node parent;

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

        public Node() {

        }

        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;
        }

        public int getValue() {
            return value;
        }

        public void setValue(int value) {
            this.value = value;
        }

        public Node getParent() {
            return parent;
        }

        public void setParent(Node parent) {
            this.parent = parent;
        }
    }
}