Linked Lists

Tarun Luthra

Agenda

What you will learn?

  • Classes & Objects Revision

  • What are Linked Lists ?

  • Basic Functionality

Classes & Objects Revision

class Node {
    int x = 0;
    int y = 0;
}
class Node:
    x = 0
    y = 0

Classes & Objects Revision

class Node {
    int x = 0;
    int y = 0;
}

class Main {
    public static void main(String[] args) {
        Node n1 = new Node();
    }
}
class Node:
    x = 0
    y = 0


def main():
    n1 = Node()


main()

Classes & Objects Revision

class Node {
    int x = 0;
    int y = 0;
}

class Main {
    public static void main(String[] args) {
        Node n1 = new Node();
        System.out.println(n1.x); // 0
        System.out.println(n1.y); // 0
    }
}
class Node:
    x = 0
    y = 0


def main():
    n1 = Node()
    print(n1.x) # 0
    print(n1.x) # 0


main()

Classes & Objects Revision

class Node {
    int x = 0;
    int y = 0;
}

class Main {
    public static void main(String[] args) {
        Node n1 = new Node();
        n1.x = 50;
        n1.y = 20;
        System.out.println(n1.x); // 50
        System.out.println(n1.y); // 20
    }
}
class Node:
    x = 0
    y = 0


def main():
    n1 = Node()
    n1.x = 50
    n1.y = 20
    print(n1.x) # 50
    print(n1.y)	# 20


main()

Classes & Objects Revision

class Node {
    int x = 0;
    int y = 0;
}

class Main {
    public static void main(String[] args) {
        Node n1 = new Node();
        n1.x = 50;
        n1.y = 20;

        Node n2 = n1;

        System.out.println(n1.x);
        System.out.println(n1.y);
    }
}
class Node:
    x = 0
    y = 0


def main():
    n1 = Node()
    n1.x = 50
    n1.y = 20

    n2 = n1

    print(n1.x)
    print(n1.y)


main()

Classes & Objects Revision

class Node {
    int x = 0;
    int y = 0;
}

class Main {
    public static void main(String[] args) {
        Node n1 = new Node();
        n1.x = 50;
        n1.y = 20;

        Node n2 = n1;
        n2.x = 100;

        System.out.println(n1.x);
        System.out.println(n1.y);
    }
}
class Node:
    x = 0
    y = 0


def main():
    n1 = Node()
    n1.x = 50
    n1.y = 20

    n2 = n1
    n2.x = 100

    print(n1.x)
    print(n1.y)


main()

class Node {
    int x = 0;
    int y = 0;
}

class Main {
    public static void main(String[] args) {
        Node n1 = new Node();
        n1.x = 50;
        n1.y = 20;

        Node n2 = n1;
        n2.x = 100;

        Node n3 = n1;

        System.out.println(n3.x); // 100
        System.out.println(n3.y); // 20
    }
}
class Node:
    x = 0
    y = 0


def main():
    n1 = Node()
    n1.x = 50
    n1.y = 20

    n2 = n1
    n2.x = 100

    n3 = n1

    print(n3.x)  # 100
    print(n3.y)  # 20


main()

class Node {
    int x = 0;
    int y = 0;
}

class Main {
    public static void main(String[] args) {
        Node n1 = new Node();
        n1.x = 50;
        n1.y = 20;

        Node n2 = n1;
        n2.x = 100;

        Node n3 = n1;

        System.out.println(n3.x); // 100
        System.out.println(n3.y); // 20

        Node n4 = new Node();
    }
}
class Node:
    x = 0
    y = 0


def main():
    n1 = Node()
    n1.x = 50
    n1.y = 20

    n2 = n1
    n2.x = 100

    n3 = n1

    print(n3.x)  # 100
    print(n3.y)  # 20

    n4 = Node()


main()

Constructors

class Node {
    int x = 0;
    int y = 0;
}

class Main {
    public static void main(String[] args) {
        Node n1 = new Node();
        n1.x = 50;
        n1.y = 20;

        Node n2 = new Node();
        n2.x = -20;
        n2.y = 10;
    }
}
class Node:
    x = 0
    y = 0


def main():
    n1 = Node()
    n1.x = 50
    n1.y = 20

    n2 = Node()
    n2.x = -20
    n2.y = 10


main()

Constructors

class Node {
    int x = 0;
    int y = 0;

    Node(int a, int b) {
        x = a;
        y = b;
    }
}

class Main {
    public static void main(String[] args) {
        Node n1 = new Node(50, 20);

        Node n2 = new Node(-20, 10);

    }
}
class Node:
    x = 0
    y = 0

    def __init__(self, a, b):
        self.x = a
        self.y = b


def main():
    n1 = Node(50, 20)

    n2 = Node(-20, 10)


main()

Can we have an object reference as a property ? 🧐

The 'next' property

class Node {
    int data = 0;
    Node next = null;
}
class Node:
    data = 0
    next = None

The 'next' property

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}
class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None

The 'next' property

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)


main()

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)


main()

data

next

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)


main()

data

next

10

null

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)


main()

data

next

10

null

t1

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
        t1.next = new Node(20);
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)
    t1.next = Node(20)


main()

data

next

10

null

t1

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
        t1.next = new Node(20);
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)
    t1.next = Node(20)


main()

data

next

10

null

t1

data

next

20

null

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
        t1.next = new Node(20);
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)
    t1.next = Node(20)


main()

data

next

10

t1

data

next

20

null

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
        t1.next = new Node(20);

        Node t2 = t1.next;
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)
    t1.next = Node(20)

    t2 = t1.next


main()

data

next

10

t1

data

next

20

null

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
        t1.next = new Node(20);

        Node t2 = t1.next;
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)
    t1.next = Node(20)

    t2 = t1.next


main()

data

next

10

t1

data

next

20

null

t2

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
        t1.next = new Node(20);

        Node t2 = t1;
        t2.next = new Node(30);
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)
    t1.next = Node(20)

    t2 = t1.next
    t2.next = Node(30)


main()

data

next

10

t1

data

next

20

null

t2

data

next

30

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
        t1.next = new Node(20);

        Node t2 = t1;
        t2.next = new Node(30);
        t2 = t2.next;

        System.out.println(t2.data);
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)
    t1.next = Node(20)

    t2 = t1.next
    t2.next = Node(30)
    t2 = t2.next

    print(t2.data)


main()

data

next

10

t1

data

next

20

null

t2

data

next

30

class Node {
    int data = 0;
    Node next = null;

    Node(int x) {
        data = x;
        next = null;
    }
}

class Main {
    public static void main(String[] args) {
        Node t1 = new Node(10);
        t1.next = new Node(20);

        Node t2 = t1;
        t2.next = new Node(30);
        t2 = t2.next;

        System.out.println(t2.data); // 30
    }
}

class Node:
    data = 0
    next = None

    def __init__(self, x):
        self.data = x
        self.next = None


def main():
    t1 = Node(10)
    t1.next = Node(20)

    t2 = t1.next
    t2.next = Node(30)
    t2 = t2.next

    print(t2.data)  # 30


main()

data

next

10

t1

data

next

20

null

t2

data

next

30

data

next

10

t1

data

next

20

null

t2

data

next

30

data

next

10

t1

data

next

20

null

t2

data

next

30

We only need head Node address to access entire chain of data.

data

next

10

t1

data

next

20

null

t2

data

next

30

This type of data structure is called a 

data

next

10

t1

data

next

20

null

t2

data

next

30

This type of data structure is called a 

Linked List

data

next

10

t1

data

next

20

null

data

next

30

Linked List

A Linked List is a linear data structure consisting of connected nodes where each node has corresponding data and a pointer to the address of the next node.

 

The first node of a linked list is called the Head, and it acts as an access point.

Time to try!

Let's begin!

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

null

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

i = 2

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

i = 2

data

next

2

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

i = 2

data

next

2

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

i = 3

data

next

2

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

i = 3

data

next

2

data

next

3

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

i = 3

data

next

2

data

next

3

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

i = 4

data

next

2

data

next

3

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

i = 4

data

next

2

data

next

3

data

next

4

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

i = 4

data

next

2

data

next

3

data

next

4

Given N > 0, create a linked list which contains data from 1 to N.

Node generateLL(int n) {
    Node head = new Node(1);
    Node temp = head;
    for (int i = 2; i <= n; i++) {
      temp.next = new Node(i);
      temp = temp.next;
    }
    return head;
}
def generateLL(n):
    head = Node(1)
    temp = head

    for i in range(2, n + 1):
        temp.next = Node(i)
        temp = temp.next
    return head

n = 4

data

next

1

head

temp

null

return head

data

next

2

data

next

3

data

next

4

Size of a Linked List 👨‍💻 

Given the head of a linked list, return its size

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

null

data

next

2

data

next

3

data

next

4

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

count = 0

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

count = 1

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

count = 1

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

count = 2

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

count = 2

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

count = 3

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

count = 4

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

count = 4

Given the head of a linked list, return its size

int size(Node head) {
    Node temp = head;
    int count = 0;
    while (temp != null) {
        count++;
        temp = temp.next;
    }
    return count;
}
def size(head):
    temp = head
    count = 0
    while temp != None:
        count += 1
        temp = temp.next
    return count

data

next

1

head

temp

null

data

next

2

data

next

3

data

next

4

return count

count = 4

Insertion

Given the head node of a linked list, insert a new node at kth index (0 based indexing)

Given the head node of a linked list, insert a new node at kth index (0 based indexing)

Node insert(Node head, int pos, int data) {
    if (pos < 0 || pos > size(head)) {
      	return head;
    }
    Node temp = head;
    Node newNode = new Node(data);
    if (pos == 0) {
        newNode.next = head;
        return newNode;
    }
    for (int i = 0; i < pos - 1; i++) {
    	temp = temp.next;
    }
    newNode.next = temp.next;
    temp.next = newNode;
    return head;
}
def insert(head, pos, data):
    if pos < 0 or pos > size(head):
        return head

    temp = head
    newNode = Node(data)

    if pos == 0:
        newNode.next = head
        return newNode

    for i in range(pos - 1):
        temp = temp.next

    newNode.next = temp.next
    temp.next = newNode
    return head

Codes 👨‍💻 

Java -

https://ide.codingminutes.com/?id=aii

Python -

https://ide.codingminutes.com/?id=aik

Thank you! 👨‍💻 

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