Check Unique Characters in Substring

This program checks if substring has unique characters.

Problem Statement

Write a Java program to check if substring "abcd" has unique characters.

Source Code

1 import java.util.HashSet;
2 public class UniqueSubstringCheck {
3 public static void main(String[] args) {
4 System.out.println("Eduinq Unique Substring Check");
5 String sub="abcd";
6 HashSet<Character> set=new HashSet<>();
7 for(char c:sub.toCharArray()){
8 if(set.contains(c)){
9 System.out.println("Substring has duplicates");
10 return;
11 }
12 set.add(c);
13 }
14 System.out.println("Substring has all unique characters");
15 }
16 }

Program Output

Eduinq Unique Substring Check
Substring has all unique characters

Explanation

A HashSet tracks each character encountered, and the loop returns immediately if a character is already present in the set, otherwise it confirms all characters are unique, demonstrating a uniqueness check.

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