Rotate String · Interview Problem

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Leetcode

Medium

Strings

Arrays

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Rotate String

Determine whether one string can be rotated to become another string.

Acceptance 100%

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String Rotation

gfg

Problem Statement

Given two strings s and goal, determine whether goal can be obtained by rotating s any number of positions.

A rotation moves some prefix of the string to the end while keeping the relative order of all characters the same. You may rotate the string zero or more times.

Return true if goal is reachable from s, otherwise return false.

Examples of a rotation

abcde -> cdeab
abcde -> deabc
Rotating by 0 positions leaves the string unchanged.

Input Format

Two strings s and goal.
Both strings consist of arbitrary characters, typically lowercase English letters in interview versions of the problem.

Output Format

Return a boolean value.
true if goal is a rotation of s, otherwise false.

Constraints

Compare lengths first: if s.length != goal.length, the answer is immediately false.
Strings may be empty.
Assume standard character equality comparisons.

Examples

Sample cases returned by the problem API.

Example 1

Input

s = "abcde", goal = "cdeab"

Output

true

Explanation

Rotating abcde left by 2 positions gives cdeab.

Example 2

Input

s = "abcde", goal = "abced"

Output

false

Explanation

No rotation of abcde can produce abced.

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