數據結構—二叉排序樹（Java）

數據結構—二叉排序樹（Java）

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說明

二叉排序樹：BST: (Binary Sort(Search) Tree), 對於二叉排序樹的任何一個非葉子節點，要求左子節點的值比當前節點的值小，右子節點的值比當前節點的值大

代碼

package cn.guizimo.binarysorttree;

public class BinarySortTree {
    public static void main(String[] args) {
        int[] arr = {7, 3, 10, 12, 5, 1, 9, 2};
        BinarySortTreeDemo binarySortTree = new BinarySortTreeDemo();
        for(int i = 0; i< arr.length; i++) {
            binarySortTree.add(new Node(arr[i]));
        }
        System.out.println("中序遍歷");
        binarySortTree.infixOrder(); // 1, 3, 5, 7, 9, 10, 12
        binarySortTree.delNode(12);
        System.out.println("當前根節點root=" + binarySortTree.getRoot());
        System.out.println("刪除後中序遍歷");
        binarySortTree.infixOrder();
    }
    
}


class BinarySortTreeDemo {
    private Node root;

    public Node getRoot() {
        return root;
    }

    //查找當前節點
    public Node search(int value) {
        if (root == null) {
            return null;
        } else {
            return root.search(value);
        }
    }

    //找到最小值
    public int delRightTreeMin(Node node) {
        Node target = node;
        while(target.left != null) {
            target = target.left;
        }
        delNode(target.value);
        return target.value;
    }

    //刪除節點
    public void delNode(int value) {
        if (root == null) {
            return;
        } else {
            //刪除葉子節點
            Node targetNode = search(value);
            if (targetNode == null) {
                return;
            }
            if (root.left == null && root.right == null) {
                root = null;
                return;
            }
            Node parent = searchParent(value);
            if (targetNode.left == null && targetNode.right == null) {
                if (parent.left != null && parent.left.value == value) {
                    parent.left = null;
                } else if (parent.right != null && parent.right.value == value) {
                    parent.right = null;
                }
                //刪除兩顆子樹的節點
            } else if (targetNode.left != null && targetNode.right != null) {
                int i = delRightTreeMin(targetNode.right);
                targetNode.value = i;
                //刪除一顆子樹的節點
            } else {
                if (targetNode.left != null) {
                    if (parent != null) {
                        if (parent.left.value == value) {
                            parent.left = targetNode.left;
                        } else {
                            parent.right = targetNode.right;
                        }
                    } else {
                        root = targetNode.left;
                    }
                } else {
                    if (parent != null) {
                        if (parent.left.value == value) {
                            parent.left = targetNode.right;
                        } else if (parent.right.value == value) {
                            parent.right = targetNode.right;
                        }
                    } else {
                        root = targetNode.right;
                    }
                }
            }
        }
    }

    //查詢當前節點的父節點
    public Node searchParent(int value) {
        if (root == null) {
            return null;
        } else {
            return root.searchParent(value);
        }
    }

    //添加節點
    public void add(Node node) {
        if (root == null) {
            root = node;
        } else {
            root.add(node);
        }
    }

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

}

class Node {
    int value;
    Node left;
    Node right;

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

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

    //查找節點
    public Node search(int value) {
        if (value == this.value) {
            return this;
        } else if (value < this.value) {
            if (this.left == null) {
                return null;
            }
            return this.left.search(value);
        } else {
            if (this.right == null) {
                return null;
            }
            return this.right.search(value);
        }
    }

    //查詢父節點
    public Node searchParent(int value) {
        if ((this.left != null && this.left.value == value) ||
                (this.right != null && this.right.value == value)) {
            return this;
        } else {
            if (value < this.value && this.left != null) {
                return this.left.searchParent(value);
            } else if (value >= this.value && this.right != null) {
                return this.right.searchParent(value);
            } else {
                return null;
            }
        }
    }

    //添加節點
    public void add(Node node) {
        if (node == null) {
            return;
        }
        if (node.value < this.value) {
            if (this.left == null) {
                this.left = node;
            } else {
                this.left.add(node);
            }
        } else {
            if (this.right == null) {
                this.right = node;
            } else {
                this.right.add(node);
            }
        }
    }

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

}

測試

感謝

尚硅谷

以及勤勞的本身

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