QUESTION:

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.

EXPLANATION:

这个是easy的题目，直接看逻辑就好了

不过我看到一个简便的办法

tmp = A+A

A.contains(B);

SOLUTION:

class Solution {
    public boolean rotateString(String A, String B) {
        if(A.equals(B)) return true;
        if(A.length()!=B.length()) return false;
        int time = 0;
        while (time<A.length()){
            String tmp = shiftString(A);
            if(tmp.equals(B)) return true;
            A = tmp;
            time++;
        }
        return false;
    }
    public String shiftString(String A){
        return A.substring(1,A.length())+A.charAt(0);
    }
}