# 796. Rotate String

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`.

```cpp
bool rotateString(string A, string B) { // time: O(n + m); space: O(n)
    string tmp = A + A;
    return A.length() == B.length() && tmp.find(B) != string::npos;
}
```
