48 lines
1.2 KiB
JavaScript
48 lines
1.2 KiB
JavaScript
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// https://www.freecodecamp.org/learn/coding-interview-prep/data-structures/create-a-doubly-linked-list
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var Node = function (data, prev) {
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this.data = data;
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this.prev = prev;
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this.next = null;
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};
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var DoublyLinkedList = function () {
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this.head = null;
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this.tail = null;
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// Only change code below this line
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this.add = (element) => {
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const node = new Node(element, this.tail);
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if (this.head === null) {
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this.head = node;
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this.tail = node;
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} else {
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this.tail.next = node;
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this.tail = node;
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}
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};
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this.remove = (element) => {
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let prevNode = null;
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let currentNode = this.head;
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while (currentNode !== null && currentNode.data !== element) {
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prevNode = currentNode;
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currentNode = currentNode.next;
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}
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if (currentNode === null || currentNode.data !== element) {
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return;
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}
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if (prevNode === null) {
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this.head = currentNode.next;
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} else {
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prevNode.next = currentNode.next;
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}
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if (currentNode.next === null) {
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this.tail = prevNode;
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} else {
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const nextNode = currentNode.next;
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nextNode.prev = prevNode;
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}
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return currentNode.element;
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};
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// Only change code above this line
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};
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