Merge pull request akshitagit#67 from XenomShox/xenomshox_branch

akshitagupta15june · web-flow · commit acbd43cf585d · 2020-10-09T10:04:10.000+05:30
Added Singly and Doubly Linked List Classes, with a bunch of methods(…
diff --git a/DataStructures/DoublyLinkedList.js b/DataStructures/DoublyLinkedList.js
@@ -0,0 +1,116 @@
+class Node {
+    constructor(val) {
+        this.val = val;
+        this.next = null;
+        this.prev = null;
+    }
+}
+
+class DoublyLinkedList {
+    constructor() {
+        this.head = null;
+        this.tail = null;
+        this.length = 0;
+    }
+    push(val) {
+        var newNode = new Node(val);
+        if (this.length === 0) {
+            this.head = newNode;
+            this.tail = newNode;
+        } else {
+            this.tail.next = newNode;
+            newNode.prev = this.tail;
+            this.tail = newNode;
+        }
+        this.length++;
+        return this;
+    }
+    pop() {
+        if (!this.head) return undefined;
+        var poppedNode = this.tail;
+        if (this.length === 1) {
+            this.head = null;
+            this.tail = null;
+        } else {
+            this.tail = poppedNode.prev;
+            this.tail.next = null;
+            poppedNode.prev = null;
+        }
+        this.length--;
+        return poppedNode;
+    }
+    shift() {
+        if (this.length === 0) return undefined;
+        var oldHead = this.head;
+        if (this.length === 1) {
+            this.head = null;
+            this.tail = null;
+        } else {
+            this.head = oldHead.next;
+            this.head.prev = null;
+            oldHead.next = null;
+        }
+        this.length--;
+        return oldHead;
+    }
+    unshift(val) {
+        var newNode = new Node(val);
+        if (this.length === 0) {
+            this.head = newNode;
+            this.tail = newNode;
+        } else {
+            this.head.prev = newNode;
+            newNode.next = this.head;
+            this.head = newNode;
+        }
+        this.length++;
+        return this;
+    }
+    get(index) {
+        if (index < 0 || index >= this.length) return null;
+        var count, current;
+        if (index <= this.length / 2) {
+            count = 0;
+            current = this.head;
+            while (count !== index) {
+                current = current.next;
+                count++;
+            }
+        } else {
+            count = this.length - 1;
+            current = this.tail;
+            while (count !== index) {
+                current = current.prev;
+                count--;
+            }
+        }
+        return current;
+    }
+    set(index, val) {
+        var foundNode = this.get(index);
+        if (foundNode != null) {
+            foundNode.val = val;
+            return true;
+        }
+        return false;
+    }
+    insert(index, val) {
+        if (index < 0 || index > this.length) return false;
+        if (index === 0) return !!this.unshift(val);
+        if (index === this.length) return !!this.push(val);
+
+        var newNode = new Node(val);
+        var beforeNode = this.get(index - 1);
+        var afterNode = beforeNode.next;
+
+        (beforeNode.next = newNode), (newNode.prev = beforeNode);
+        (newNode.next = afterNode), (afterNode.prev = newNode);
+        this.length++;
+        return true;
+    }
+}
+
+var list = new DoublyLinkedList();
+list.push("Harry");
+list.push("Ron");
+list.push("Hermione");
diff --git a/DataStructures/SinglyLinkedList.js b/DataStructures/SinglyLinkedList.js
@@ -0,0 +1,138 @@
+class Node {
+    constructor(val) {
+        this.val = val;
+        this.next = null;
+    }
+}
+
+class SinglyLinkedList {
+    constructor() {
+        this.head = null;
+        this.tail = null;
+        this.length = 0;
+    }
+    push(val) {
+        var newNode = new Node(val);
+        if (!this.head) {
+            this.head = newNode;
+            this.tail = this.head;
+        } else {
+            this.tail.next = newNode;
+            this.tail = newNode;
+        }
+        this.length++;
+        return this;
+    }
+    pop() {
+        if (!this.head) return undefined;
+        var current = this.head;
+        var newTail = current;
+        while (current.next) {
+            newTail = current;
+            current = current.next;
+        }
+        this.tail = newTail;
+        this.tail.next = null;
+        this.length--;
+        if (this.length === 0) {
+            this.head = null;
+            this.tail = null;
+        }
+        return current;
+    }
+    shift() {
+        if (!this.head) return undefined;
+        var currentHead = this.head;
+        this.head = currentHead.next;
+        this.length--;
+        if (this.length === 0) {
+            this.tail = null;
+        }
+        return currentHead;
+    }
+    unshift(val) {
+        var newNode = new Node(val);
+        if (!this.head) {
+            this.head = newNode;
+            this.tail = this.head;
+        }
+        newNode.next = this.head;
+        this.head = newNode;
+        this.length++;
+        return this;
+    }
+    get(index) {
+        if (index < 0 || index >= this.length) return null;
+        var counter = 0;
+        var current = this.head;
+        while (counter !== index) {
+            current = current.next;
+            counter++;
+        }
+        return current;
+    }
+    set(index, val) {
+        var foundNode = this.get(index);
+        if (foundNode) {
+            foundNode.val = val;
+            return true;
+        }
+        return false;
+    }
+    insert(index, val) {
+        if (index < 0 || index > this.length) return false;
+        if (index === this.length) return !!this.push(val);
+        if (index === 0) return !!this.unshift(val);
+
+        var newNode = new Node(val);
+        var prev = this.get(index - 1);
+        var temp = prev.next;
+        prev.next = newNode;
+        newNode.next = temp;
+        this.length++;
+        return true;
+    }
+    remove(index) {
+        if (index < 0 || index >= this.length) return undefined;
+        if (index === 0) return this.shift();
+        if (index === this.length - 1) return this.pop();
+        var previousNode = this.get(index - 1);
+        var removed = previousNode.next;
+        previousNode.next = removed.next;
+        this.length--;
+        return removed;
+    }
+    reverse() {
+        var node = this.head;
+        this.head = this.tail;
+        this.tail = node;
+        var next;
+        var prev = null;
+        for (var i = 0; i < this.length; i++) {
+            next = node.next;
+            node.next = prev;
+            prev = node;
+            node = next;
+        }
+        return this;
+    }
+    print() {
+        var arr = [];
+        var current = this.head;
+        while (current) {
+            arr.push(current.val);
+            current = current.next;
+        }
+        console.log(arr);
+    }
+}
+
+var list = new SinglyLinkedList();
+
+list.push(100);
+list.push(201);
+list.push(250);
+list.push(350);
+list.push(999);
+
+list.print();
diff --git a/DataStructures/add b/DataStructures/add
