官解

func lengthOfLongestSubstring(s string) int {n := len(s)ans := 0subMap := make(map[byte]int)for i, j := 0, 0; j < n; j++ {if v, ok := subMap[byte(s[j])]; ok {if i < v {i = v}}if ans < (j - i + 1) {ans = j - i + 1}subMap[byte(s[j])] = j + 1}return ans
}