Question 4 : How to check if one String is rotation of another String in java?

 Solution: Let’s say you want to check whether str1 and str2 is the rotation of one another or not.

1. Create a new String with str3= str1 + str1
2. Check if str3 contains str2 or not.
3. if str3 contains str2 then str2 is the rotation of str1 else it is not

4. Let's say you need to check whether str1 and str2 is the rotation of one another or not.

• Create a new String with str3= str1 + str1
• Check if str3 contains str2 or not.
• if str3 contains str2 then str2 is rotation of str1 else it is not

• Java Program to check if one String is the rotation of another.

package org.cloudTechtwitter;
 
public class StringRotationMain {
 
    public static void main(String[] args) {
 
        System.out.println(
                "CloudTechtwitter and TechtwitterCloud are rotation of each other : " + isRotation("CloudTechtwitter", "TechtwitterCloud"));
        System.out.println(
                "CloudTechtwitter and TechCloudtwitter are rotation of each other : " + isRotation("CloudTechtwitter", "TechCloudtwitter"));
 
    }
 
    public static boolean isRotation(String str, String rotation) {
        String str2 = str + str;
 
        if (str2.contains(rotation)) {
            return true;
        }
        return false;
 
    }
 
}

Python Code 

def is_rotation(s1: str, s2: str) -> bool:
    if len(s1) != len(s2):
        return False
    return (s1 + s1).find(s2) != -1

print(is_rotation("CloudTechtwitter", "TechtwitterCloud"))  # True
print(is_rotation("CloudTechtwitter", "TechCloudtwitter"))  # False

📌 Final Comparison

  
    
    
    
    
  

  

    
Approach
    
Time Complexity
    
Space Complexity
    
Best Use
  

  

    

      Double the first string and check if second is a substring
    
    
O(n)
    
O(n)
    

      ⭐ Best and simple rotation check
    
  

  

    

      Naive nested loop substring search
    
    
O(n²)
    
O(1)
    

      Basic but slow approach
    
  

  

    

      Built-in substring functions (contains / find)
    
    
O(n)
    
O(1)
    

      ✔ Clean standard library method