Find longest substring without repeating characters.

Given a string, find the longest substrings without repeating characters. Iterate through the given string, find the longest maximum substrings.

Kotlin program to find longest substring without repeating characters

import java.util.HashSet

fun subString(input: String): String {

    val set = HashSet()

    var longestOverAll = ""
    var longestTillNow = ""

    for (i in 0 until input.length) {
        val c = input[i]

        if (set.contains(c)) {
            longestTillNow = ""
        longestTillNow += c
        if (longestTillNow.length > longestOverAll.length) {
            longestOverAll = longestTillNow

    return longestOverAll

fun main(args: Array) {
    val input = "substringfindout"



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