无重复字符的最长子串

func lengthOfLongestSubstring(s string)int{
	var length = 0
	var max = 0
	var start = 0//慢指针
	var end = 0//快指针
	for end<len(s){
		tmpChar:=s[end]
		for i:=start;i<end;i++{
			if tmpChar==s[i]{
				start = i+1
				length = end-start
				break
			}
		}
		length++
                end++
		max = int(math.Max(float64(length), float64(max)))
	}

	return max
}