蓝桥杯练习题 找出唯一成对的数【java省赛】

import java.util.Random;

public class Main {
    public static void main(String[] args) {
        int n = 1001;     //n为数组长度
        int[] arr = new int[n];
        for(int i = 0; i < arr.length - 1; i++){
            arr[i] = i + 1;
        }

        //把最后一个数设置为随机数
        arr[arr.length - 1] = new Random().nextInt(n - 1) + 1;  //生成1-10之间的整数
        //随机下标
        int index = new Random().nextInt(n);    //生成0-10之间的整数

        //打乱数组顺序
        int temp = arr[index];
        arr[index] = arr[arr.length - 1];
        arr[arr.length - 1] = temp;

        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();

        //连续异或可以去重
        int x = 0;
        for (int i = 1; i <= n - 1; i++) {
            x = (x ^ i);
        }
        for (int i = 0; i < n; i++) {
            x = x ^ arr[i];
        }
        System.out.println(x);
        System.out.println("==========");
        //使用辅助空间检查结果是否正确
        int[] arrsHelp = new int[n];
        for (int i = 0; i < arr.length; i++) {
            arrsHelp[arr[i]]++;
        }
        for (int i = 0; i < arr.length; i++) {
            if(arrsHelp[i] == 2){
                System.out.println(i);
            }
        }

    }
}