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 

bool rotateString(char* A, char* B) 
{
    if(NULL == A || NULL == B)
        return false;
    
    int lena = strlen(A);
    int lenb = strlen(B);
    /*length not equal*/
    if(lena != lenb)
        return false;
    
    char *pos = NULL;
    
    char *AA = (char *)malloc((2 * lena +1) *sizeof(char));
    snprintf(AA,2*lena + 1,"%s%s",A,A);
    
    /*whether B is substr of AA*/
    pos = strstr(AA,B);
    if(pos)
        return true;
    
    return false;
    
    
}