素数伴侣 java

package com.patience.interview.huawei;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

/**
 * 素数伴侣
 * @author Green.Gee
 * @date 2022/9/4 11:37
 * @email green.gee.lu@gmail.com
 */
public class PrimeCouple {

    public static void main(String[] args) throws IOException {
        /**
         * 奇数偶数 分组
         * 循环奇数组 找到偶数组中能够奇数匹配的素数伴侣
         * 已有伴侣的偶数则让给后来可以重新找到伴侣的
         */
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.valueOf(br.readLine());
        String [] lines = br.readLine().split("\\s");
        List<Integer> odds = new ArrayList<>(8);
        List<Integer> evens = new ArrayList<>(8);
        for(String i : lines){
            int item = Integer.valueOf(i);
            if(item % 2 == 1){
                odds.add(item);
            }
            if(item % 2 == 0){
                evens.add(item);
            }
        }

        int count = 0;
        int [] matchEvens = new int[evens.size()];
        for(int odd : odds){
            boolean [] v = new boolean[evens.size()];
            if(find(odd,matchEvens,evens,v)){
                count++;
            }
        }
        System.out.println(count);
    }

    static boolean find(int odd,int[] matchEvens,List<Integer> evens,boolean[] v){
        for (int i = 0; i < evens.size(); i++){
            boolean prime = isPrime(odd + evens.get(i));
            if(prime && !v[i]){
                v[i] = true;
                // try again to understand
                if(matchEvens[i] == 0 || find(matchEvens[i],matchEvens,evens,v)){
                    matchEvens[i] = odd;
                    return true;
                }
            }
        }
        return false;
    }

    private static boolean isPrime(int n) {
        if(n == 1) return false;
        for (int i = 2;i <= (int)Math.sqrt(n); i++){
            if(n % i == 0)
                return false;
        }
        return true;
    }
}