Shawniqua Greene: Data Structures I

src/hash-table.js

@@ -15,20 +15,19 @@ class HashTable {
   // If the key already exists in the bucket, the newer value should overwrite the older value associated with that key
   insert(key, value) {
 
-  }
+    };
   // Removes the key, value pair from the hash table
   // Fetch the bucket associated with the given key using the getIndexBelowMax function
   // Remove the key, value pair from the bucket
   remove(key) {
-    
-  }
+
+  };
 
   // Fetches the value associated with the given key from the hash table
   // Fetch the bucket associated with the given key using the getIndexBelowMax function
   // Find the key, value pair inside the bucket and return the value
   retrieve(key) {
-    
-  }
+
+  };
 }
-
 module.exports = HashTable;

src/linked-list.js

@@ -9,17 +9,45 @@ class LinkedList {
   // If the list is empty, the new element is considered the tail as well as the head
   // If there is one element in the list before the new element is added, the new element becomes the tail of the list
   addToTail(value) {
+    const node = {
+      next: null,
+      value,
+    };
 
+    if (this.tail === null) {
+      this.tail = node;
+      this.head = node;
+      return;
+    }
+    this.tail.next = node;
+    this.tail = node;
   }
   // Removes the current head node from the list, replacing it with the next element in the list
   // Returns the value of the removed node
   removeHead() {
-
+    if (this.head === null) {
+      return;
+    }
+    const value = this.head.value;
+    this.head = this.head.next;
+    return value;
   }
   // Checks the linked list for the given value
   // Returns true if the the value is found in the list, false otherwise
   contains(value) {
-
+    if (this.head === null) {
+      return false;
+    }
+    const find = (node) => {
+      if (node.value === value) {
+        return true;
+      }
+      if (node.next === null) {
+        return false;
+      }
+      return (find(node.next));
+    };
+    return (find(this.head));
   }
 }
 

src/queue.js

@@ -5,7 +5,24 @@
   4. Add a `dequeue` method that removes the item in the queue that was added earliest
 */
 class Queue {
+  constructor() {
+    this.storage = [];
+  }
+
+  get size() {
+    return this.storage.length;
+  }
+
+  enqueue(item) {
+    this.storage.push(item);
+    return this.size;
+  }
+
+  dequeue(item) {
+    return this.storage.shift(item);
+  }
 
 }
 
+
 module.exports = Queue;

src/stack.js

@@ -5,6 +5,23 @@
   4. Add a `pop` method that removes the most recently-added item to the stack
 */
 class Stack {
+  constructor() {
+    this.storage = [];
+    this.counter = 0;
+  }
+
+  get size() {
+    return this.counter;
+  }
+
+  push(item) {
+    this.storage.push(item);
+    return this.counter++;
+  }
+
+  pop(item) {
+    return this.storage.pop(item);
+  }
 
 }