BST 구현

자료구조/Tree/passwd10/binarySearchTree.test.js

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+/* 
+왼쪽자식노드는 오른쪽자식노드보다 작아야한다.
+*/
+
+class Node {
+ constructor(data) {
+ this.data = data;
+ this.left = null;
+ this.right = null;
+ }
+}
+
+class BinarySearchTree {
+ constructor() {
+ this.root = null;
+ }
+
+ insert(data) {
+ const node = new Node(data);
+
+ this.root = this.insertNode(this.root, node);
+ }
+
+ insertNode(root, node) {
+ if (!root) {
+ return node;
+ }
+
+ root.data <= node.data ?
+ root.right = this.insertNode(root.right, node) :
+ root.left = this.insertNode(root.left, node)
+
+ return root;
+ }
+
+ delete(data) { // no child | one child | 2 children
+ if (!this.root) {
+ console.log('비어있는 트리입니다.')
+ return;
+ }
+
+ this.deleteNode(this.root, data);
+ }
+
+ deleteNode(root, data) {
+ if (root === null) {
+ return root;
+ }
+ if (data < root.data) {
+ root.left = this.deleteNode(root.left, data);
+ }
+ if (data > root.data) {
+ root.right = this.deleteNode(root.right, data);
+ }
+ if (data === root.data) {
+ if (!root.left && !root.right) { // no child
+ return null;
+ }
+ if (!root.left) { // 1 child
+ return root.right;
+ }
+ if (!root.right) { // 1 child
+ return root.left;
+ }
+ // 2 children
+ root = this.getMin(root.right); //가장 작은값으로 현재 root노드 대체
+ root.right = this.deleteNode(root.right, root.data); //찾았던 가장 작은값 삭제
+ }
+ return root;
+ }
+
+ find(root, data) {
+ if (root.data === data) {
+ return root;
+ }
+
+ if (root.data < data) {
+ return this.find(root.right, data);
+ }
+
+ return this.find(root.left, data);
+ }
+
+ getMin(root) {
+ if (root.left === null) {
+ return root;
+ }
+ return this.getMin(root.left);
+ }
+
+ getMax() {
+ if (root.right === null) {
+ return root;
+ }
+ return this.getMax(root.right);
+ }
+
+ inOrder() { // 중위순회(왼쪽 - 자신 - 오른쪽)
+ return this.inOrderNode(this.root, []);
+ }
+
+ inOrderNode(root, result) {
+ if (root !== null) {
+ this.inOrderNode(root.left, result);
+ result.push(root.data);
+ this.inOrderNode(root.right, result);
+ }
+ return result;
+ }
+
+ search(value) {
+ return this.searchNode(this.root, value);
+ }
+
+ searchNode(root, value) {
+ if (root.data < value) {
+ return this.searchNode(root.right, value);
+ }
+ if (root.data > value) {
+ return this.searchNode(root.left, value);
+ }
+ return root;
+ }
+}
+
+test('Insert', () => {
+ const tree = new BinarySearchTree();
+
+ tree.insert(5);
+ tree.insert(1);
+ tree.insert(2);
+ tree.insert(4);
+ tree.insert(6);
+ tree.insert(7);
+ tree.insert(8);
+
+ expect(tree.inOrder()).toEqual([1, 2, 4, 5, 6, 7, 8]);
+});
+
+test.only('Delete', () => {
+ const tree = new BinarySearchTree();
+
+ tree.insert(5);
+ tree.insert(1);
+ tree.insert(2);
+ tree.insert(4);
+ tree.insert(6);
+ tree.insert(7);
+ tree.insert(8);
+
+ tree.delete(4);
+
+ expect(tree.inOrder()).toEqual([ 1, 2, 5, 6, 7, 8 ]);
+});
+
+test('getMin', () => {
+ const tree = new BinarySearchTree();
+ const root = tree.root;
+
+ tree.insert(3);
+ tree.insert(2);
+ tree.insert(1);
+ tree.insert(4);
+ tree.insert(5);
+
+ expect(tree.getMin(root).data).toEqual(1);
+});
+
+test.only('search', () => {
+ const tree = new BinarySearchTree();
+
+ tree.insert(3);
+ tree.insert(2);
+ tree.insert(1);
+ tree.insert(4);
+ tree.insert(5);
+
+ expect(tree.search(1)).toEqual({ data: 1, left: null, right: null });
+});