<p>字符串轮转。给定两个字符串<code>s1</code>和<code>s2</code>,请编写代码检查<code>s2</code>是否为<code>s1</code>旋转而成(比如,<code>waterbottle</code>是<code>erbottlewat</code>旋转后的字符串)。</p> <p><strong>示例1:</strong></p> <pre><strong> 输入</strong>:s1 = "waterbottle", s2 = "erbottlewat" <strong> 输出</strong>:True </pre> <p><strong>示例2:</strong></p> <pre><strong> 输入</strong>:s1 = "aa", s2 = "aba" <strong> 输出</strong>:False </pre> <ol> </ol> <p><strong>提示:</strong></p> <ol> <li>字符串长度在[0, 100000]范围内。</li> </ol> <p><strong>说明:</strong></p> <ol> <li>你能只调用一次检查子串的方法吗?</li> </ol>