Beginner Exercises

Here's some starter code for you. The starter code includes a class definition for a single Node in a list, and a class that keeps track of an entire list starting with the root.

Exerises problems ask you to start with the list in one state and write code that transforms it into another state. For example, this "problem A" is asking you to write code to remove the first item from a list:

// Problem A
// 1 2 3
// 2 3
var listA = makeList([1, 2, 3]);
console.log(listA.toString());

// example solution for Problem A
listA.root = listA.root.next;

Try to write code to solve these problems:

function Node(data) {
  this.data = data;
  this.next = undefined;
}

function LinkedList() {
  this.root = undefined;
}

LinkedList.prototype.toString = function() {
  var current = this.root;
  var result = "";
  while (current !== undefined) {
    result += " " + current.data;
    current = current.next;
  }

  return result;
}


// problem 1
// 1 3 4
// 1 2 3 4
var list1 = makeList([1, 3, 4]);
console.log(list1.toString());

// your manipulations here

console.log(list1.toString());
console.log();


// problem 2
// 1 2 3 4 5 6 7
// 1 2 3 4 5 6 7 8
var list2 = makeList([1, 2, 3, 4, 5, 6, 7]);
console.log(list2.toString());

// your manipulations here

console.log(list2.toString());
console.log();


// problem 3
// 1 2 3 4 5 6 8
// 1 2 3 4 5 6 7 8
var list3 = makeList([1, 2, 3, 4, 5, 6, 8]);
console.log(list3.toString());

// your manipulations here

console.log(list3.toString());
console.log();


// problem 4
// 1 2 3
// 2 3
var list4 = makeList([1, 2, 3]);
console.log(list4.toString());

// your manipulations here

console.log(list4.toString());
console.log();

// problem 5
// 34 45 78
// undefined
var list5 = makeList([34, 45, 78]);
console.log(list5.toString());
// your manipulations here
list5.root = undefined;

console.log(list5.toString());
console.log();

// problem 6
// 23 17 8
// 23 23 17 17 8 8
var list6 = makeList([23, 17, 8]);
console.log(list6.toString());

// your manipulations here

console.log(list6.toString());
console.log();

// problem 7
// 3 4 5 6
// 6 5 4 3
var list7 = makeList([3, 4, 5, 6]);
console.log(list7.toString());

// your manipulations here

console.log(list7.toString());
console.log();


// DO NOT MODIFY!!
// Helper functions to set up lists for each problem.

function makeList(a) {
  var list = new LinkedList();
  list.root = new Node(a[0]);

  var current = list.root;
  for (var i = 1; i < a.length; i++) {
    current.next = new Node(a[i]);
    current = current.next;
  }

  return list;
}