寻找最长不含有重复字符的子串 示例

package main

import (
    "fmt"
)

func lengthOfNonRepeatSubStr(s string) int {
    lastOccured := make(map[rune]int) //记录每个字符最后出现的位置
    start := 0
    maxLength := 0
    for i, ch := range []rune(s) {
        if lastI, ok := lastOccured[ch]; ok && lastI >= start {
            start = lastI + 1

        }
        if i-start+1 > maxLength {
            maxLength = i - start + 1
        }
        lastOccured[ch] = i
    }
    return maxLength

}

func main() {
    fmt.Println(lengthOfNonRepeatSubStr("abcabcbb"))
    fmt.Println(lengthOfNonRepeatSubStr("bbbb"))
    fmt.Println(lengthOfNonRepeatSubStr("pwwkew"))
    fmt.Println(lengthOfNonRepeatSubStr("我已经不知道屏蔽的标准是什么了，不就是题目耸了点么也屏蔽啊"))

}

输出

3

1

3

16

思路： 

对于每一个字母x

lastOccured[x]不存在，或者<start   -----》无需操作

lastOccured[x] >= start  ----->更新start

更新lastOccured[x],更新maxLength