796. Rotate String

796. Rotate String

Difficulty: Easy

Topics: String, String Matching

Given two strings s and goal, return true if and only if s can become goal after some number of shifts on s.

A shift on s consists of moving the leftmost character of s to the rightmost position.

• For example, if s = "abcde", then it will be "bcdea" after one shift.

Example 1:

• 
  Input: s = "abcde", goal = "cdeab"


• 
  Output: true

Example 2:

• 
  Input: s = "abcde", goal = "abced"


• 
  Output: false

Constraints:

• 1 <= s.length, goal.length <= 100


• 
  s and goal consist of lowercase English letters.

Solution:

We can take advantage of the properties of string concatenation. Specifically, if we concatenate the string s with itself (i.e., s + s), all possible rotations of s will appear as substrings within that concatenated string. This allows us to simply check if goal is a substring of s + s.

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