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92 lines
2.2 KiB
92 lines
2.2 KiB
"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"]; |