Rotate String

看一个字符串B不是左旋后的A. 只需要把A复制一下, 然后看其中有没有B即可.

class Solution {
    public boolean rotateString(String A, String B) {
        if(A.length() != B.length()) // must has same length
            return false;
        else {
            String C = A + A;
            if(C.contains(B))// rotate and same
                return true;
        }
        return false;
    }
}