92 lines
2.2 KiB
JavaScript
92 lines
2.2 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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// Simple doubly linked list (https://en.wikipedia.org/wiki/Doubly_linked_list) implementation
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// used for queues. This implementation assumes that the node provided by the user can be modified
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// to adjust the next and last properties. We implement only the minimal functionality
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// for queue support.
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class DLL {
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constructor() {
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this.head = this.tail = null;
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this.length = 0;
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}
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removeLink(node) {
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if (node.prev) node.prev.next = node.next;else this.head = node.next;
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if (node.next) node.next.prev = node.prev;else this.tail = node.prev;
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node.prev = node.next = null;
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this.length -= 1;
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return node;
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}
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empty() {
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while (this.head) this.shift();
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return this;
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}
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insertAfter(node, newNode) {
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newNode.prev = node;
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newNode.next = node.next;
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if (node.next) node.next.prev = newNode;else this.tail = newNode;
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node.next = newNode;
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this.length += 1;
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}
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insertBefore(node, newNode) {
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newNode.prev = node.prev;
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newNode.next = node;
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if (node.prev) node.prev.next = newNode;else this.head = newNode;
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node.prev = newNode;
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this.length += 1;
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}
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unshift(node) {
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if (this.head) this.insertBefore(this.head, node);else setInitial(this, node);
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}
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push(node) {
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if (this.tail) this.insertAfter(this.tail, node);else setInitial(this, node);
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}
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shift() {
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return this.head && this.removeLink(this.head);
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}
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pop() {
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return this.tail && this.removeLink(this.tail);
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}
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toArray() {
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return [...this];
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}
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*[Symbol.iterator]() {
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var cur = this.head;
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while (cur) {
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yield cur.data;
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cur = cur.next;
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}
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}
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remove(testFn) {
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var curr = this.head;
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while (curr) {
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var { next } = curr;
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if (testFn(curr)) {
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this.removeLink(curr);
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}
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curr = next;
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}
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return this;
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}
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}
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exports.default = DLL;
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function setInitial(dll, node) {
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dll.length = 1;
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dll.head = dll.tail = node;
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}
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module.exports = exports.default; |