package main

func LongestDupSubstringBruteforce(s string) string {
	strLen := len(s)
	if strLen < 2 {
		return ""
	}

	res := ""
	for ln := 1; ln < strLen; ln++ {
		for i := 0; i <= strLen-ln; i++ {
			word1 := s[i : i+ln]
			count := 0
			for j := 0; j <= strLen-ln; j++ {
				word2 := s[j : j+ln]
				if word1 == word2 {
					count++
					if count > 1 {
						res = word1
						break
					}
				}
			}
		}
	}

	return res
}

func LongestDupSubstringReversedBruteforce(s string) string {
	strLen := len(s)
	if strLen < 2 {
		return ""
	}

	for ln := strLen - 1; ln >= 1; ln-- {
		for i := strLen - ln; i >= 0; i-- {
			word1 := s[i : i+ln]
			count := 0
			for j := strLen - ln; j >= 0; j-- {
				word2 := s[j : j+ln]
				if word1 == word2 {
					count++
					if count > 1 {
						return word1
					}
				}
			}
		}
	}

	return ""
}

func LongestDupSubstring(s string) string {
	return LongestDupSubstringBruteforce(s)
}