Earth - Emily

lib/queue.js

@@ -1,38 +1,94 @@
+// had to look at geekforgeeks for reference..
+
 class Queue {
-    constructor() {
-        // this.store = ...
-        throw new Error("This method has not been implemented!");
+    constructor(size = 20) {
+        this.store = new Array(size);
+        this.front = this.back = -1;
+        this.size = size;
     }
 
     enqueue(element) {
-        throw new Error("This method has not been implemented!");
+        if ((this.back + 1) % this.size === this.front) {
+            throw newError("Full Queue!");
+        } else if (this.front === -1) {
+            //if empty 
+            this.front = 0;
+            this.back = 0;
+            this.store[this.back] = element;
+        } else if (this.back === this.size - 1 && this.front !== 0) {
+            this.back = 0;
+            this.store[this.back] = element;
+        } else {
+            console.log("HERE", this.store)
+            this.back = (this.back + 1) % this.size;
+            this.store[this.back] = element;
+        }; 
     }
 
     dequeue() {
-        throw new Error("This method has not been implemented!");
+        // let temp = null;
+
+        // let data = this.store[this.front];
+        // this.store[this.front] = null;
+
+        // if (this.front === -1) {
+        //     throw newError("Empty Queue!");
+        // } else if (this.front === this.back) {
+        // //    let temp = this.store[this.front];
+        //     this.front = -1;
+        //     this.back = -1;
+        //     // return temp;
+        // } else {
+        //     // temp = this.store[this.front];
+        //     this.store[this.front] = null;
+        //     this.front = (this.front + 1) % this.size;
+        //     // return temp;
+        // }
+        // return data;
+        if (this.front === -1) throw newError("Empty Queue!");
+
+        let data = this.store[this.front];
+        this.store[this.front] = null;
+
+        //if the queue is empty
+        if (this.front === this.back) {
+            console.log("DEQUEUE")
+
+            this.front = -1;
+            this.back = -1;
+        } else if (this.front === this.size - 1) {
+            console.log("DEQUEUE")
+
+            this.front = 0;
+        } else {
+            console.log("DEQUEUE")
+            this.front = (this.front + 1) % this.size;
+        }
+
+        return data;
     }
 
     front() {
-        throw new Error("This method has not been implemented!");
+        return this.store[this.front];
     }
 
     size() {
-        throw new Error("This method has not been implemented!");
+        return this.store.size;
     }
 
     isEmpty() {
-        throw new Error("This method has not been implemented!");
+       return this.front === -1;
     }
 
     toString() {
         let arr;
-        if (this.head > this.tail) {
-            arr = this.store.slice(this.head, this.capacity).concat(this.store.slice(0, this.tail));
+        if (this.front > this.back) {
+            arr = this.store.slice(this.front, this.size).concat(this.store.slice(0, this.back + 1));
         } else {
             arr = this.store
         }
         return JSON.stringify(arr.filter((v) => v !== null));
     }
 }
 
-module.exports = Queue;
+module.exports = Queue;

lib/stack.js

@@ -1,23 +1,27 @@
+const LinkedList = require("./linked-list");
+
 class Stack {
     constructor() {
-        // this.store = ...
-        throw new Error("This method has not been implemented!");
+      this.store = new LinkedList();
     }
 
-    push() {
-        throw new Error("This method has not been implemented!");
+    push(value) {
+      this.store.addFirst(value);
     }
 
     pop() {
-        throw new Error("This method has not been implemented!");
+      let first = this.store.getFirst();
+
+      this.store.delete(first);
+      return first;
     }
 
     isEmpty() {
-        throw new Error("This method has not been implemented!");
+      return this.store.isEmpty();
     }
 
     toString() {
-        JSON.stringify(this.store);
+      JSON.stringify(this.store);
     }
 }