Custom Combination and permutation program ~ HTML Title Kartik Mandal

package com.kartik;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
*
* @author kartik
* Blog www.kartikchandramandal.blogspot.com
* One of the best way to do permutation of a data set is to by applying permutation , it help making all combination of a specified length
*/
public class Permutations<T> {
public static void main(String args[]) {
System.out.println("Integer permutation below:");
//Integer permutation
Permutations<Integer> obj = new Permutations<Integer>();
Collection<Integer> input = new ArrayList<Integer>();
input.add(1);
input.add(2);
input.add(3);
Collection<List<Integer>> output = obj.permute(input);
int k = 0;
Set<List<Integer>> pnr = null;
for (int i = 0; i <= input.size(); i++) {
pnr = new HashSet<List<Integer>>();
for(List<Integer> integers : output){
pnr.add(integers.subList(i, integers.size()));
}
k = input.size()- i;
System.out.println("P("+input.size()+","+k+") :"+ "Count ("+pnr.size()+") :- "+pnr);
}
System.out.println("Character permutation and combination below:");
//String permutation
Permutations<String> objStr = new Permutations<String>();
Collection<String> inputStr = new ArrayList<String>();
inputStr.add("K");
inputStr.add("A");
inputStr.add("R");
inputStr.add("T");
/* inputStr.add("I");*/
Collection<List<String>> outputStr = objStr.permute(inputStr);
int len = 0;
Set<List<String>> pnrStr = null;
for (int i = 0; i <= inputStr.size(); i++) {
pnrStr = new HashSet<List<String>>();
for(List<String> integers : outputStr){
pnrStr.add(integers.subList(i, integers.size()));
}
len = input.size()- i;
if(i==0){
System.out.println("P("+inputStr.size()+","+len+") :"+ "Count ("+pnrStr.size()+") :- "+pnrStr);
}
}
}
public Collection<List<T>> permute(Collection<T> input) {
Collection<List<T>> output = new ArrayList<List<T>>();
if (input.isEmpty()) {
output.add(new ArrayList<T>());
return output;
}
List<T> list = new ArrayList<T>(input);
T head = list.get(0);
List<T> rest = list.subList(1, list.size());
for (List<T> permutations : permute(rest)) {
List<List<T>> subLists = new ArrayList<List<T>>();
for (int i = 0; i <= permutations.size(); i++) {
List<T> subList = new ArrayList<T>();
subList.addAll(permutations);
subList.add(i, head);
subLists.add(subList);
}
output.addAll(subLists);
}
return output;
}
}
Output:
Integer permutation below:
P(3,3) :Count (6) :- [[1, 2, 3], [2, 3, 1], [3, 2, 1], [3, 1, 2], [2, 1, 3], [1, 3, 2]]
P(3,2) :Count (6) :- [[3, 1], [2, 1], [3, 2], [1, 3], [2, 3], [1, 2]]
P(3,1) :Count (3) :- [[3], [1], [2]]
P(3,0) :Count (1) :- [[]]
Character permutation and combination below:
P(4,3) :Count (24) :- [[R, T, A, K], [R, K, T, A], [T, A, R, K], [T, R, K, A], [A, T, R, K], [A, T, K, R], [R, A, T, K], [T, R, A, K], [R, A, K, T], [R, T, K, A], [K, T, A, R], [A, R, T, K], [A, K, R, T], [A, R, K, T], [T, K, R, A], [K, A, T, R], [K, R, T, A], [T, A, K, R], [T, K, A, R], [K, R, A, T], [A, K, T, R], [K, A, R, T], [K, T, R, A], [R, K, A, T]]

About Kartik Chandra Mandal

I am Kartik Chandra Mandal from Bangalore, India. Working as software engineer in Java technology. Have good knowledge of OWASP and CSRF in security for applications and it's implementation in Java technology.

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