package norepeat

func max(x, y int) int {
	if x > y {
		return x
	}
	return y
}

func lengthOfLongestSubstring(s string) int {
	positions := map[byte]int{}
	longest := 0

	for i := 0; i < len(s); i++ {
		char := s[i]
		pos, exists := positions[char]
		positions[char] = i
		longest = max(longest, len(positions))
		if exists {
			positions = map[byte]int{}
			i = pos
		}
	}

	return longest
}

func LengthOfLongestSubstring(s string) int {
	return lengthOfLongestSubstring(s)
}