Add Data Structures by Zakkarat

submissions/Zakkarat/data-structures/list.js

@@ -0,0 +1,67 @@
+const Node = require('./node');
+
+class List {
+  constructor () {
+    this._head = null;
+    this._size = 0;
+  }
+
+  insert (searchNode, value) {
+    let currNode = this._head;
+    if (this._head) {
+      if (this._head.getValue() === searchNode) {
+        this._head = new Node(value, null, this._head);
+        this._size += 1;
+        return;
+      }
+      currNode = this.getTo(this._head, searchNode);
+      currNode.setNext(value);
+    } else {
+      this._head = new Node(value, null, null);
+    }
+    this._size += 1;
+  }
+
+  getTo (node, value) {
+    if (!node.getNext() || !node.getNext().getValue() || node.getNext().getValue() === value) {
+      return node;
+    }
+    return this.getTo(node.getNext(), value);
+  }
+
+  show () {
+    let tempNode = this._head;
+    return [...Array(this._size).keys()].map(_ => {
+      const value = tempNode.getValue();
+      tempNode = tempNode.getNext();
+      return value;
+    }).join('->');
+  }
+
+  remove (value, node) {
+    if (node === 'head') {
+      node = this._head;
+      if (node.getValue() === value) {
+        this._head = node.getNext();
+        this._size -= 1;
+        return;
+      }
+    }
+    if (!node.getNext()) {
+      return;
+    }
+    if (node.getNext().getValue() === value) {
+      if (!node.getNext().getNext()) {
+        node.setNext(null);
+        this._size -= 1;
+        return;
+      }
+      node.setNext(node.getNext().getNext().getValue());
+      this._size -= 1;
+      return;
+    }
+    return this.remove(value, node.getNext());
+  }
+}
+
+module.exports = List;

submissions/Zakkarat/data-structures/node.js

@@ -0,0 +1,25 @@
+class Node {
+  constructor (value, prevNode, nextNode) {
+    this._value = value;
+    this._prevNode = prevNode;
+    this._nextNode = nextNode;
+  }
+
+  getValue () {
+    return this._value;
+  }
+
+  getPrev () {
+    return this._prevNode;
+  }
+
+  getNext () {
+    return this._nextNode;
+  }
+
+  setNext (value) {
+    this._nextNode = value ? new Node(value, null, this._nextNode) : null;
+  }
+}
+
+module.exports = Node;

submissions/Zakkarat/data-structures/server.js

@@ -0,0 +1,53 @@
+const http = require('http');
+const Stack = require('./stack');
+const List = require('./list');
+const port = 3000;
+const stackInst = new Stack();
+const listInst = new List();
+const requestHandler = (req, resp) => {
+  const url = req.url.slice(1).split('/');
+  if (url[0] === '') {
+    resp.end('Choose stack or list in URL');
+  }
+  if (url[0] === 'stack') {
+    if (req.method === 'GET') {
+      if (url[1] === 'top') {
+        resp.end(stackInst.top());
+      }
+      if (url[1] === 'size') {
+        resp.end(stackInst.size());
+      }
+      if (url[1] === 'pop') {
+        resp.end(stackInst.pop());
+      }
+    }
+    if (req.method === 'POST') {
+      req.on('data', (data) => stackInst.push(data.toString()));
+      resp.end();
+    }
+  }
+  if (url[0] === 'list') {
+    if (req.method === 'POST') {
+      req.on('data', data => {
+        const { successor, value } = JSON.parse(data.toString());
+        listInst.insert(successor, value);
+      });
+      resp.end();
+    }
+    if (req.method === 'GET') {
+      resp.end(listInst.show());
+    }
+    if (req.method === 'DELETE') {
+      listInst.remove(url[1], 'head');
+      resp.end();
+    }
+  }
+};
+const server = http.createServer(requestHandler);
+
+server.listen(port, (err) => {
+  if (err) {
+    return console.log('something bad happened', err);
+  }
+  console.log(`server is listening on ${port}`);
+});

submissions/Zakkarat/data-structures/stack.js

@@ -0,0 +1,36 @@
+const Node = require('./node');
+
+class Stack {
+  constructor () {
+    this._top = null;
+    this._size = 0;
+  }
+
+  top () {
+    if (this._top) {
+      return this._top.getValue();
+    }
+    return 'Empty stack';
+  }
+
+  size () {
+    return this._size.toString();
+  }
+
+  push (value) {
+    this._top = new Node(value, this._top);
+    this._size += 1;
+  }
+
+  pop () {
+    let currTop;
+    if (this._size) {
+      [this._top, currTop] = [this._top.getPrev(), this._top];
+      this._size -= 1;
+      return currTop.getValue();
+    }
+    return 'No elements in stack';
+  }
+}
+
+module.exports = Stack;