Java_Learning/24_Recursion_Part2/duplicateString.java at main · TORRYNN/Java_Learning · GitHub

24 lines (19 loc) · 617 Bytes

import java.util.HashSet;

public class duplicateString {

static String dup(String input,HashSet<Character> seen,int i, StringBuilder output) {

if(i==input.length()){

return output.toString();

}

char ch=input.charAt(i);

if(!seen.contains(ch)){

seen.add(ch);

output.append(ch);

}

return dup(input,seen,i+1,output);

}

public static void main(String[] args){

String st="prathampratham";

HashSet<Character> seen=new HashSet<>();

System.out.println(dup(st,seen,0,new StringBuilder()));

}

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