Decoded

Arrays

A collection of elements stored in contiguous memory locations.

Types of Arrays

Static Array

A static array has a fixed size defined at creation and cannot grow or shrink during runtime.

10
0
20
1
30
2
40
3
4
Dynamic Array

A dynamic array can resize automatically as elements are added or removed, allowing flexible storage.

10
0
20
1
30
2
40
3
...
1D Array

A 1D array is a linear collection of elements stored in a single row.

10
0
20
1
30
2
40
3
2D Array

A 2D array stores elements in rows and columns like a table or matrix.

1
0,0
2
0,1
3
1,0
4
1,1
3D Array (2x2x2)

A 3D array stores elements in multiple layers, where a 2×2×2 array has 2 layers each containing a 2×2 grid.

Layer 0

1
0,0,0
2
0,0,1
3
0,1,0
4
0,1,1

Layer 1

5
1,0,0
6
1,0,1
7
1,1,0
8
1,1,1

Traversal

10
0
20
1
30
2
40
3
50
4

Time Complexity: O(n)

Access

10
0
20
1
30
2
40
3
50
4

Time Complexity: O(1)

Insertion

10
0
20
1
40
2
50
3
4

Time Complexity: O(n) due to shifting elements.

Deletion

10
0
20
1
30
2
40
3
50
4

Time Complexity: O(n) due to shifting elements.

Update

10
0
20
1
30
2
99
3
50
4

Time Complexity: O(1)

Search

Linear Search (O(n))

Checks elements sequentially until the target is found.

10
0
50
1
30
2
70
3
20
4
Binary Search (O(log n))

Repeatedly divides a sorted array to find a target efficiently.

10
0
20
1
30
2
50
3
70
4
Low: 0Mid: -High: 4

Time Complexity Summary

OperationTime ComplexityNotes
AccessO(1)
UpdateO(1)
TraversalO(n)Visit every element
SearchO(n) / O(log n)Linear scan / Binary search (if sorted)
InsertionO(n)Requires shifting elements
DeletionO(n)Requires shifting elements

When to Use Arrays

  • When you need fast random access to elements using an index (O(1)).
  • For storing a collection of elements of the same data type, ensuring memory efficiency.
  • Arrays are commonly used to implement other data structures like stacks, queues, and heaps due to efficient indexed memory access.