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package byteDance;

import java.util.HashMap;

/**

* Created by lizeyang on 2020/5/16.

* 请从字符串中找出一个最长的不包含重复字符的子字符串，计算该最长子字符串的长度。

public class test46 {

//时间复杂度O(n)，额外空间复杂度O(n)

public static int test(String s){

if(s==null||s.length()==0){

return 0;

}

HashMap<Character,Integer> map = new HashMap<>();

int left = 0,maxLen = 0;

for(int i=0;i<s.length();i++){

if(map.containsKey(s.charAt(i))){

left = Math.max(left,map.get(s.charAt(i))+1);

}

map.put(s.charAt(i),i);

maxLen = Math.max(maxLen,i-left+1);

}

return maxLen;

}

public static void main(String[] args) {

String s= "pwwkew";

System.out.println(test(s));

}