Visual Comparison Of Linked Lists

This file uses Mermaid diagrams to compare linked list structures and operations.

Singly Linked List

mermaid flowchart LR A[Head] --> B[10] B --> C[20] C --> D[30] D --> E[NULL]

Each node only knows the next node.

Doubly Linked List

mermaid flowchart LR A[NULL] <--> B[10] B <--> C[20] C <--> D[30] D <--> E[NULL]

Each node knows both previous and next.

Circular Linked List

mermaid flowchart LR A[10] --> B[20] B --> C[30] C --> A

The last node points back to the first node.

Insert At Front In Singly Linked List

mermaid flowchart LR A[New 5] --> B[10] B --> C[20] C --> D[30]

Only a few pointer changes are needed, so it is O(1).

Delete Front In Singly Linked List

```mermaid flowchart LR A[Head] --> B[10] B --> C[20] C --> D[30]

E[After Delete] --> F[20]
F --> G[30]

```

Linked Stack

mermaid flowchart LR A[Top] --> B[30] B --> C[20] C --> D[10] D --> E[NULL]

Push and pop happen at the top, so both are O(1).

Linked Queue

mermaid flowchart LR A[Front] --> B[10] B --> C[20] C --> D[30] D --> E[NULL] F[Rear] --> D

Enqueue at rear and dequeue at front are both O(1) when front and rear are stored.

One-Page Comparison

```mermaid flowchart TD A[Linked Lists] --> B[Singly] A --> C[Doubly] A --> D[Circular]

B --> B1[One next pointer]
B --> B2[Simple]
B --> B3[No backward move]

C --> C1[Prev and next pointers]
C --> C2[Move both directions]
C --> C3[More memory]

D --> D1[Last links to first]
D --> D2[Good for cycles]
D --> D3[Useful with tail pointer]

```