Showing posts with label Permutation. Show all posts
Showing posts with label Permutation. Show all posts

String Permutation using Recursion

Lets see simple program to print all Permutations of given string using Recursion call.



import java.util.TreeSet;

public class Permutation {

 static TreeSet<String> combination = new TreeSet<String>();

 public static void main(String[] args) {
  String str = "ABCD";
  permutation("", str);
  printAllCombination();
 }

 private static void permutation(String prefix, String str) {
  int len = str.length();
  if (len == 0) {
   combination.add(prefix);
  } else {
   for (int i = 0; i < len; i++) {

    String p = prefix + str.charAt(i);
    String s = str.substring(0, i) + str.substring(i + 1, len);

    permutation(p, s);
   }
  }
 }

 private static void printAllCombination() {
  int index = 0;
  for (String string : combination) {
   System.out.println(++index + "\t : " + string);
  }
 }
}


OUTPUT:


1  : ABCD
2  : ABDC
3  : ACBD
4  : ACDB
5  : ADBC
6  : ADCB
7  : BACD
8  : BADC
9  : BCAD
10  : BCDA
11  : BDAC
12  : BDCA
13  : CABD
14  : CADB
15  : CBAD
16  : CBDA
17  : CDAB
18  : CDBA
19  : DABC
20  : DACB
21  : DBAC
22  : DBCA
23  : DCAB
24  : DCBA