stack lab

solution.js

@@ -1,5 +1,147 @@
 const { nums, words } = require("./data/data.js");
 const { inspect } = require("util");
+// stacks LIFO
+class Node {
+  constructor(data) {
+    this.data = data;
+    this.next = null;
+  }
+}
+class Stack {
+  constructor(top = null) {
+    this.top = top;
+  }
+
+  push(keys){
+    const newNode = new Node(keys) 
+    newNode.next = this.top
+    this.top = newNode;
+ }
+
+size(){
+    let count = 0
+    let currentTop = this.top 
+    while(currentTop){
+       count++
+       currentTop = currentTop.next
+     }
+     return count
+}
+
+ pop(){
+   if(this.top == null) {
+     throw new Error ("Stack is empty")
+   }
+   let currentTop = this.top;
+     if(currentTop = this.top){
+      const newTop = currentTop.next
+        this.top = newTop
+        return currentTop
+     }
+    }
+     isEmpty(){
+      return !this.top
+     }
+
+  findMin(){
+    let min = 0
+    let currentTop = this.top
+    while(currentTop){
+      if(currentTop.keys < min){
+         min = currentTop.keys
+      }
+       currentTop = currentTop.next
+    }
+     return min
+
+   }
+
+peek(){
+  if(!this.top){
+    throw new Error("Stack is empty")
+  }
+   return this.top
+ }
+
+
+
+
+
+
+}
+
+
+class Queue {
+   constructor(max = null) {
+     this.first = null;
+     this.last = null;
+     this.size = 0;
+     this.max = max;
+   }
+
+   enqueue(data){
+     let newNode = new Node(data)
+       if(!this.first){
+         this.first = newNode
+         this.last = newNode
+       }
+        else {
+           this.last.next = newNode
+           this.last = newNode
+        }
+         return ++this.size
+   }
+
+   dequeue() {
+    if(this.first == null){
+      throw new Error("Queue is empty")
+    }
+     const firstNode = this.first
+     if(this.first === this.last){
+       this.last = null
+   }
+      this.first = this.first.next
+      this.size--
+      return firstNode.data
+     }
+
+     count() {
+      let count = 0
+      let currentTop = this.first
+      while(currentTop){
+        count++
+        currentTop = currentTop.next
+      }
+       return count
+    }
+    isEmpty(){
+      return !this.first
+    }
+
+    peek(){
+      if(!this.first){
+        throw new Error("Queue is empty")
+      }
+        return this.first
+    }
+
+    getLast(){
+      return this.last
+    }
+
+    findMax(){
+      let max = 0;
+      let currentTop = this.first
+      while(currentTop){
+        if(currentTop.data > max){
+          max = currentTop.data
+        }
+        currentTop = currentTop.next
+      }
+         return max
+     }
+   }
+
 
 module.exports = {
   Node,