StringRotation.java

package misc;
/**
 * Algorithm:-
 *  1. Create a temp string and store concatenation of str1 to str1 in temp.
 *                   temp = str1.str1
 *   2. If str2 is a substring of temp then str1 and str2 are 
 *      rotations of each other.
 *
 *  Example:                 
 *                    str1 = "ABACD"
 *                    str2 = "CDABA"
 *
 *    temp = str1.str1 = "ABACDABACD"
 *    Since str2 is a substring of temp, str1 and str2 are 
 *    rotations of each other.
 *
 */

public class StringRotation {

	static boolean isRotation(String str1, String str2) {
		return (str1.length() == str2.length()) && ((str1 + str2).indexOf(str2) != -1);
	}
	public static void main(String[] args) {
		String str1 = "AACD";
		String str2 = "ACDA";
		if(isRotation(str1, str2)) {
			System.out.println("Strings are rotations of each other");
		} else {
			System.out.println("Strings are not rotations of each other");
		}

	}

}