NetEase网易 Java笔试题 给定一个字符串，请返回满足以下条件的最长字符串的长度：“a”、“b“、“c”、“x”、“y“、“z”在字符串中都恰好出现了偶数次（0也是偶数）

import java.util.*;
public class Main{
    public static void main(String[] args)
    {
        Scanner scanner = new Scanner(System.in);
        String next = scanner.next();
        System.out.println(findTheLongestSubstring(next));
    }
    private static int findTheLongestSubstring(String s)
    {
        Map<Integer, Integer> map = new HashMap<>();
        int state = 0;
        int maxLen = 0; 
        map.put(0, -1);   
        for (int i = 0; i < s.length(); i++)
        {           
            if (s.charAt(i) == 'a')
                state ^= 0x000001;      
            if (s.charAt(i) == 'b')
                state ^= 0x000010;      
            if (s.charAt(i) == 'c')
                state ^= 0x000100;       
            if (s.charAt(i) == 'x')
                state ^= 0x001000;       
            if (s.charAt(i) == 'y')
                state ^= 0x010000;       
            if (s.charAt(i) == 'z')
                state ^= 0x100000;       
            if (map.containsKey(state))
            {            
                maxLen = Math.max(maxLen, i - map.get(state));         
            }
            else
            {     
                map.put(state, i);  
            }   
        }     
        return maxLen;   
    }
}