Javascript/Math: editing file name

Data-Structures/Queue/Queue.js

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+/* Queue
+* A Queue is a data structure that allows you to add an element to the end of
+* a list and remove the item at the front. A queue follows a "First In First Out"
+* system, where the first item to enter the queue is the first to be removed. This
+* implementation uses an array to store the queue.
+*/
+
+// Functions: enqueue, dequeue, peek, view, length
+
+var Queue = (function () {
+  // constructor
+  function Queue () {
+    // This is the array representation of the queue
+    this.queue = []
+  }
+
+  // methods
+  // Add a value to the end of the queue
+  Queue.prototype.enqueue = function (item) {
+    this.queue[this.queue.length] = item
+  }
+
+  // Removes the value at the front of the queue
+  Queue.prototype.dequeue = function () {
+    if (this.queue.length === 0) {
+      throw new Error('Queue is Empty')
+    }
+
+    var result = this.queue[0]
+    this.queue.splice(0, 1) // remove the item at position 0 from the array
+
+    return result
+  }
+
+  // Return the length of the queue
+  Queue.prototype.length = function () {
+    return this.queue.length
+  }
+
+  // Return the item at the front of the queue
+  Queue.prototype.peek = function () {
+    return this.queue[0]
+  }
+
+  // List all the items in the queue
+  Queue.prototype.view = function () {
+    console.log(this.queue)
+  }
+
+  return Queue
+}())
+
+// Implementation
+var myQueue = new Queue()
+
+myQueue.enqueue(1)
+myQueue.enqueue(5)
+myQueue.enqueue(76)
+myQueue.enqueue(69)
+myQueue.enqueue(32)
+myQueue.enqueue(54)
+
+myQueue.view()
+
+console.log('Length: ' + myQueue.length())
+console.log('Front item: ' + myQueue.peek())
+console.log('Removed ' + myQueue.dequeue() + ' from front.')
+console.log('New front item: ' + myQueue.peek())
+console.log('Removed ' + myQueue.dequeue() + ' from front.')
+console.log('New front item: ' + myQueue.peek())
+myQueue.enqueue(55)
+console.log('Inserted 55')
+console.log('New front item: ' + myQueue.peek())
+
+for (var i = 0; i < 5; i++) {
+  myQueue.dequeue()
+  myQueue.view()
+}
+
+// console.log(myQueue.dequeue()); // throws exception!

Data-Structures/Queue/QueueUsing2Stacks.js

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+// implementation of Queue using 2 stacks
+// contribution made by hamza chabchoub for a university project
+
+class Queue {
+  constructor () {
+    this.inputStack = []
+    this.outputStack = []
+  }
+
+  // Push item into the inputstack
+  enqueue (item) {
+    this.inputStack.push(item)
+  }
+
+  dequeue (item) {
+    // push all items to outputstack
+    this.outputStack = []
+    if (this.inputStack.length > 0) {
+      while (this.inputStack.length > 0) {
+        this.outputStack.push(this.inputStack.pop())
+      }
+    }
+    // display the top element of the outputstack
+    if (this.outputStack.length > 0) {
+      console.log(this.outputStack.pop())
+      // repush all the items to the inputstack
+      this.inputStack = []
+      while (this.outputStack.length > 0) {
+        this.inputStack.push(this.outputStack.pop())
+      }
+    }
+  }
+
+  // display elements of the inputstack
+  listIn () {
+    let i = 0
+    while (i < this.inputStack.length) {
+      console.log(this.inputStack[i])
+      i++
+    }
+  }
+
+  // display element of the outputstack
+  listOut () {
+    let i = 0
+    while (i < this.outputStack.length) {
+      console.log(this.outputStack[i])
+      i++
+    }
+  }
+}
+
+// testing
+
+const queue = new Queue()
+queue.enqueue(1)
+queue.enqueue(2)
+queue.enqueue(8)
+queue.enqueue(9)
+
+console.log(queue.dequeue())
+// ans = 1
+console.log(queue.dequeue())
+// ans = 2