toj2440.java

java 实现的一些算法： 赛选法求素数

package daniel.toj;

import java.util.Arrays;
import java.util.Scanner;

public class Toj2440 {
	public static final int MAX_SIZE = 10;
	private static int [] t = new int[MAX_SIZE];
	public static int res = 0;
	private static int f(int n){
		if(n == 1)return t[0];
		if(n == 2)return t[1];
		if(n == 3)return t[0] + t[1] + t[2];
		if(2*t[1] > t[0]+t[n-2]){
			res = t[0]+t[0]+t[n-2]+t[n-1];
		}
		else {
			res = t[0]+t[1]+t[1]+t[n-1];
		}
		res += f(n-2);
		return res;
	}
	public static  void main(String [] args){
		Scanner scan = new Scanner(System.in);
		while(scan.hasNext()){
			int n = scan.nextInt();
			for(int i =0 ;i<n;i++){
				t[i] = scan.nextInt();
			}
			Arrays.sort(t, 0, n);
			res = 0;
			System.out.println(f(n));
		}
	}
}