Check whether a string is a rotation of another string using Java .....

here is the code....

Problem - "ravgau" is a rotation of "gaurav".

       

public class Demo {

 public static void main(String[] args) {

  String s1 = "gaurav";
  String s2 = "avgaur";

  if (isSubString(s1 + s1, s2))
   System.out.print("String :" + s2 + " is a rotation of string :" + s1);
  else
   System.out.print("String :" + s2 + " is not a rotation of string :" + s1);

 }

 public static boolean isSubString(String s1, String s2) {
  int k = 0;
  int i = 0;
  int t;
  if (s1.length() < s2.length()) {
   return false;
  } else {
   while (i < (s1.length() - s2.length() + 1)) {
    if (s1.charAt(i) == s2.charAt(k)) {
     t = i;
     t++;
     k++;
     // Always make sure that conditions in loop should appear in
     // correct order otherwise it could give an exception
     while ((k < s2.length()) && (s1.charAt(t) == s2.charAt(k))) {
      t++;
      k++;
     }
     if (k == s2.length())
      return true;
     else
      k = 0;
    }
    i++;
   }
  }
  return false;
 }
}

       
 

Remove duplicates from a string without using any additional data structure using Java....

here is the code .....

       

public class Demo {

 public static void main(String[] args) {
  String name = "GAURAV KUMAR YADAV1111";
  dupliactesRemoved(name);
 }

 //This method assumes that string is made up of only small letter characters i. "a....z"
 public static void dupliactesRemoved(String temp) {

  int vector = 0;
  int val;
  System.out.println("Given string after removing duplicates characters is below :");
  for (int i = 0; i < temp.length(); i++) {
   val = temp.charAt(i) - 'a';
   if ((vector & (1 << val)) == 0) {
    System.out.print(temp.charAt(i));
    vector = vector | (1 << val);
   }
  }
 }
}

       
 

Determine if a string has all unique characters without using any additional data structure using Java....

Here is the the code ....

       
public class Demo {

 public static void main(String[] args) {

  String name = "gaurv1";
  if (isUniqueCharString(name))
   System.out.print("String is made up of unique chars");
  else
   System.out.print("String is not made up of unique chars");

 }

 //here we are using an integer as a bit vector....
 public static boolean isUniqueCharString(String temp) {
  int vector = 0;
  int val;
  for (int i = 0; i < temp.length(); i++) {
   val = temp.charAt(i) - 'a';
   if ((vector & (1 << val)) > 0)
    return false;
   vector = vector | (1 << val);
  }
  return true;
 }

 // Alternate solution - we can sort the characters of string and then
 // compare the neighbors
}