Left Rotate an Array by One Place

Algorithm Steps

Given an array arr of size n.
Store the first element in a temporary variable first.
Shift all elements of the array one position to the left (from index 1 to n-1).
Assign first to the last index of the array.
The array is now left-rotated by one place.

Left Rotate an Array by One Place - Optimal Solution Code

Python

JavaScript

Java

C++

def left_rotate_by_one(arr):
    if not arr:
        return arr
    first = arr[0]
    for i in range(1, len(arr)):
        arr[i - 1] = arr[i]
    arr[-1] = first
    return arr

# Sample Input
arr = [10, 20, 30, 40, 50]
print("After Left Rotation:", left_rotate_by_one(arr))

Detailed Step by Step Example

Let's left rotate the array by one position.

{ "array": [10,20,30,40,50], "showIndices": true }

Store the first element 10 in a temporary variable.

Shift index 1

Move 20 from index 1 to index 0.

{ "array": [20,20,30,40,50], "showIndices": true, "highlightIndices": [0], "labels": { "0": "updated" } }

Shift index 2

Move 30 from index 2 to index 1.

{ "array": [20,30,30,40,50], "showIndices": true, "highlightIndices": [1], "labels": { "1": "updated" } }

Shift index 3

Move 40 from index 3 to index 2.

{ "array": [20,30,40,40,50], "showIndices": true, "highlightIndices": [2], "labels": { "2": "updated" } }

Shift index 4

Move 50 from index 4 to index 3.

{ "array": [20,30,40,50,50], "showIndices": true, "highlightIndices": [3], "labels": { "3": "updated" } }

Place the first element at the end

Set 10 to index 4.

{ "array": [20,30,40,50,10], "showIndices": true, "highlightIndices": [4], "labels": { "4": "rotated" } }

Final Result:

Array after left rotation: [20, 30, 40, 50, 10]

Left Rotate an Array by One Place - Optimal Solution

Visualization

Algorithm Steps