题目123456789

Question

题目1234567891011121314151+6

Answer 1

import java.util.ArrayList;
import java.util.List;

public class Demo {
    // 开方：最高效
    private static List<Integer> getSuShu(int num) {
        List<Integer> suShuList = new ArrayList<>();
        boolean isSuShu;
        for (int i = 2; i <= num; i++) {
            if (i == 1 || (i % 2 == 0 && i != 2)) {
                continue; //偶数和1排除
            }
            isSuShu = true;
            for (int j = 2; j <= Math.sqrt(i); j++) {
                if (i % j == 0) {
                    isSuShu = false;
                    break;
                }
            }
            if (isSuShu) {
                suShuList.add(i);
            }
        }
        return suShuList;
    }

    public static void main(String[] args) {
        List<Integer> suShuList = getSuShu(10000);
        int avg = 0, sum = 0;
        // < 8000
        Integer value1 = 0;
        // > 1000
        Integer value2 = 10000;
        for (Integer integer : suShuList) {
            if(integer < 8000){
                value1 = value1 > integer ? value1 : integer;
            }
            if(integer > 1000){
                value2 = value2 < integer ? value2 : integer;
            }
            sum += integer;
        }

        System.out.println("素数的平均值" + sum/suShuList.size());
        System.out.println("小于8000的最大素数:" + value1);
        System.out.println("大于1000的最小素数:" + value2);
    }
}