Add solution #622

Author: JoshCrozier

README.md

@@ -471,6 +471,7 @@
 611|[Valid Triangle Number](./0611-valid-triangle-number.js)|Medium|
 617|[Merge Two Binary Trees](./0617-merge-two-binary-trees.js)|Easy|
 621|[Task Scheduler](./0621-task-scheduler.js)|Medium|
+622|[Design Circular Queue](./0622-design-circular-queue.js)|Medium|
 628|[Maximum Product of Three Numbers](./0628-maximum-product-of-three-numbers.js)|Easy|
 637|[Average of Levels in Binary Tree](./0637-average-of-levels-in-binary-tree.js)|Easy|
 643|[Maximum Average Subarray I](./0643-maximum-average-subarray-i.js)|Easy|

solutions/0622-design-circular-queue.js

@@ -0,0 +1,98 @@
+/**
+ * 622. Design Circular Queue
+ * https://leetcode.com/problems/design-circular-queue/
+ * Difficulty: Medium
+ *
+ * Design your implementation of the circular queue. The circular queue is a linear data structure
+ * in which the operations are performed based on FIFO (First In First Out) principle, and the
+ * last position is connected back to the first position to make a circle. It is also called
+ * "Ring Buffer".
+ *
+ * One of the benefits of the circular queue is that we can make use of the spaces in front of
+ * the queue. In a normal queue, once the queue becomes full, we cannot insert the next element
+ * even if there is a space in front of the queue. But using the circular queue, we can use the
+ * space to store new values.
+ *
+ * Implement the MyCircularQueue class:
+ * - MyCircularQueue(k) Initializes the object with the size of the queue to be k.
+ * - int Front() Gets the front item from the queue. If the queue is empty, return -1.
+ * - int Rear() Gets the last item from the queue. If the queue is empty, return -1.
+ * - boolean enQueue(int value) Inserts an element into the circular queue. Return true if the
+ *   operation is successful.
+ * - boolean deQueue() Deletes an element from the circular queue. Return true if the operation
+ *   is successful.
+ * - boolean isEmpty() Checks whether the circular queue is empty or not.
+ * - boolean isFull() Checks whether the circular queue is full or not.
+ *
+ * You must solve the problem without using the built-in queue data structure in your programming
+ * language.
+ */
+
+/**
+ * @param {number} k
+ */
+var MyCircularQueue = function(k) {
+  this.queue = new Array(k);
+  this.size = k;
+  this.front = -1;
+  this.rear = -1;
+};
+
+/**
+ * @param {number} value
+ * @return {boolean}
+ */
+MyCircularQueue.prototype.enQueue = function(value) {
+  if (this.isFull()) {
+    return false;
+  }
+  if (this.isEmpty()) {
+    this.front = 0;
+  }
+  this.rear = (this.rear + 1) % this.size;
+  this.queue[this.rear] = value;
+  return true;
+};
+
+/**
+ * @return {boolean}
+ */
+MyCircularQueue.prototype.deQueue = function() {
+  if (this.isEmpty()) {
+    return false;
+  } else if (this.front === this.rear) {
+    this.front = -1;
+    this.rear = -1;
+  } else {
+    this.front = (this.front + 1) % this.size;
+  }
+  return true;
+};
+
+/**
+ * @return {number}
+ */
+MyCircularQueue.prototype.Front = function() {
+  return this.isEmpty() ? -1 : this.queue[this.front];
+};
+
+/**
+ * @return {number}
+ */
+MyCircularQueue.prototype.Rear = function() {
+  return this.isEmpty() ? -1 : this.queue[this.rear];
+};
+
+/**
+ * @return {boolean}
+ */
+MyCircularQueue.prototype.isEmpty = function() {
+  return this.front === -1;
+};
+
+/**
+ * @return {boolean}
+ */
+MyCircularQueue.prototype.isFull = function() {
+  return (this.rear + 1) % this.size === this.front;
+};