LongestUniqueSubstring.java

package com.sarvesh.javabasics;

import java.util.HashSet;

public class LongestUniqueSubstring {

 public static void main(String[] args) {
 String stream = "abcabcbb"; 
 int maxLength = lengthOfLongestSubstring(stream);
 System.out.println("Longest unique packet sequence length: " + maxLength);
 }

 public static int lengthOfLongestSubstring(String s) {
 
 HashSet<Character> set = new HashSet<>();
 int left = 0;
 int right = 0;
 int maxLength = 0;
 
 while (right < s.length()) {
 char currentChar = s.charAt(right);
 
 while ( set.contains(currentChar)) {
 set.remove(s.charAt(left));
 left++;
 }
 maxLength = Math.max(maxLength,right-left+ 1);
 right++;
 }
 return maxLength;
 }
}