HDOJ 1262 寻找素数对

HDACM 1262

用到小范围的素数习惯性打表，用到时只要遍历即可，节约时间。

import java.util.Scanner;public class Main{    public static void main(String[] args) {        boolean prime[] = new boolean[20000];        prime[1] = true;        for (int i = 2; i < prime.length; i++) {            if (!prime[i]) {                for (int j = i*2; j < prime.length; j += i) {                    prime[j] = true;                }            }        }        Scanner sc = new Scanner(System.in);        while (sc.hasNext()) {            int n = sc.nextInt();            for (int i = n/2; i >0; i--) {                if (!prime[i] && !prime[n-i]) {                    System.out.println(i+" "+(n-i));                    break;                }            }        }    }}