poj1906

组合数学

import java.io.*;
import java.util.*;
import java.math.*;

public class Main {
    static void work(BigInteger n) {
        BigInteger x = new BigInteger("2");
        int i = 0;
        while (x.subtract(BigInteger.valueOf(1)).compareTo(n)< 0)
        {
            x = x.multiply(BigInteger.valueOf(2));
            i++;
        }
        x = x.divide(new BigInteger("2"));
        if (n.equals(x))
        {
            System.out.print(BigInteger.valueOf(3).pow(i));
            return;
        }
        work(n.subtract(x));
        System.out.print(", " + BigInteger.valueOf(3).pow(i));
    }

    public static void main(String[] args) {
        Scanner cin = new Scanner(new BufferedInputStream(System.in));
        while (cin.hasNext()) {
            BigInteger a = cin.nextBigInteger();
            if (a.equals(new BigInteger("0")))
                break;
            System.out.print("{ ");
            if (a.equals(new BigInteger("1"))) {
                System.out.println("}");
                continue;
            }
            work(a.subtract(new BigInteger("1")));
            System.out.println(" }");
        }
    }
}