Formatted question description: https://leetcode.ca/all/796.html

796. Rotate String (Easy)

We are given two strings, A and B.

A shift on A consists of taking string A and moving the leftmost character to the rightmost position. For example, if A = 'abcde', then it will be 'bcdea' after one shift on A. Return True if and only if A can become B after some number of shifts on A.

Example 1:
Input: A = 'abcde', B = 'cdeab'
Output: true

Example 2:
Input: A = 'abcde', B = 'abced'
Output: false

Note:

  • A and B will have length at most 100.

Companies:
Apple, Microsoft

Solution 1.

// OJ: https://leetcode.com/problems/rotate-string/
// Time: O(N^2)
// Space: O(N)
class Solution {
public:
    bool rotateString(string A, string B) {
        return A.size() == B.size() && (A + A).find(B) != string::npos;
    }
};

Java

  • class Solution {
        public boolean rotateString(String A, String B) {
            return A.length() == B.length() && (B + B).indexOf(A) >= 0;
        }
    }
    
  • // OJ: https://leetcode.com/problems/rotate-string/
    // Time: O(N)
    // Space: O(N)
    class Solution {
    public:
        bool rotateString(string s, string goal) {
            return goal.size() == s.size() && (s + s).find(goal) != string::npos;
        }
    };
    
  • class Solution(object):
        def rotateString(self, A, B):
            """
            :type A: str
            :type B: str
            :rtype: bool
            """
            if A == B == "":
                return True
            for i in range(len(A)):
                if A[i:] + A[:i] == B:
                    return True
            return False
    

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