String Manipulation String Hash Map Counting Character Pattern Matching
Learner Level

Implement the checkStringRotation method that checks whether one string is a rotation of another string.

The input contains two strings, first and second. Your task is to check whether second can be created by rotating first.

A rotation moves characters from the beginning of a string to the end without changing their order. For example, waterbottle rotated by five characters becomes erbottlewat.

Example 1
Input:
first (string) = waterbottle
second (string) = erbottlewat
Return:
(boolean) true
Example 2
Input:
first (string) = abcde
second (string) = cdeab
Return:
(boolean) true
Example 3
Input:
first (string) = abcde
second (string) = abced
Return:
(boolean) false

Two strings can be rotations only if they have the same length.

If second is a rotation of first, it must appear inside first + first. Doubling the first string contains every possible rotation as a substring.

So, first compare lengths, then check whether the second string exists in the doubled string.

Pseudocode:

function checkStringRotation(first, second):
    if length(first) != length(second):
        return false
    doubled = first + first
    if doubled contains second:
        return true
    return false
Run your code to see the result.