双色球概率分析

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package test;
import java.math.BigInteger;
import java.math.BigDecimal;
/**
 * 2011-3-19
 * @author Jasper
 */
public class RedandBlue {
    public static void main(String[] args) {
        System.out.println("双色球中奖概率（6/33+1/16）：");
        BigInteger allOdds = getOdds(33,6).multiply(getOdds(16,1));
        BigInteger odds1 = getOdds(6,6).multiply(getOdds(1,1));
        BigInteger odds2 = getOdds(6,6).multiply(getOdds(15,1));
        BigInteger odds3 = getOdds(6,5).multiply(getOdds(27,1)).multiply(getOdds(1,1));
        BigInteger odds4 = getOdds(6,5).multiply(getOdds(27,1)).multiply(getOdds(15,1)).add(getOdds(6,4).multiply(getOdds(27,2)).multiply(getOdds(1,1)));
        BigInteger odds5 = getOdds(6,4).multiply(getOdds(27,2)).multiply(getOdds(15,1)).add(getOdds(6,3).multiply(getOdds(27,3)).multiply(getOdds(1,1)));
        BigInteger odds6 = getOdds(6,2).multiply(getOdds(27,4)).multiply(getOdds(1,1)).add(getOdds(6,1).multiply(getOdds(27,5)).multiply(getOdds(1,1))).add(getOdds(27,6).multiply(getOdds(1,1)));
        BigInteger odds1_7 = odds1.add(odds2).add(odds3).add(odds4).add(odds5).add(odds6);
        BigInteger odds7 = allOdds.add(odds1_7.negate());
        String odds11 = BigDecimal.valueOf(odds1.longValue()).divide(BigDecimal.valueOf(allOdds.longValue()),8,BigDecimal.ROUND_HALF_EVEN).toPlainString();
        String odds21 = BigDecimal.valueOf(odds2.longValue()).divide(BigDecimal.valueOf(allOdds.longValue()),8,BigDecimal.ROUND_HALF_EVEN).toPlainString();
        String odds31 = BigDecimal.valueOf(odds3.longValue()).divide(BigDecimal.valueOf(allOdds.longValue()),8,BigDecimal.ROUND_HALF_EVEN).toPlainString();
        String odds41 = BigDecimal.valueOf(odds4.longValue()).divide(BigDecimal.valueOf(allOdds.longValue()),4,BigDecimal.ROUND_HALF_EVEN).toPlainString();
        String odds51 = BigDecimal.valueOf(odds5.longValue()).divide(BigDecimal.valueOf(allOdds.longValue()),4,BigDecimal.ROUND_HALF_EVEN).toPlainString();
        String odds61 = BigDecimal.valueOf(odds6.longValue()).divide(BigDecimal.valueOf(allOdds.longValue()),4,BigDecimal.ROUND_HALF_EVEN).toPlainString();
        String odds71 = BigDecimal.valueOf(odds7.longValue()).divide(BigDecimal.valueOf(allOdds.longValue()),4,BigDecimal.ROUND_HALF_EVEN).toPlainString();
 
        double check=(new Double(odds11))+(new Double(odds21))+(new Double(odds31))+(new Double(odds41))+(new Double(odds51))+(new Double(odds61))+(new Double(odds71));
        System.out.println("一等奖（中6+1）中奖概率："+odds1+"/"+allOdds+"="+odds11);
        System.out.println("二等奖（中6+0）："+odds2+"/"+allOdds+"="+odds21);
        System.out.println("三等奖（中5+1）(3000元）中奖概率："+odds3+"/"+allOdds+"="+odds31);
        System.out.println("四等奖（中5+0或4+1）(200元）中奖概率："+odds4+"/"+allOdds+"="+odds41);
        System.out.println("五等奖（中4+0或3+1）(10元）中奖概率："+odds5+"/"+allOdds+"="+odds51);
        System.out.println("六等奖（中2+1或1+1或0+1）(5元）中奖概率："+odds6+"/"+allOdds+"="+odds61);
        System.out.println("不中奖概率："+odds7+"/"+allOdds+"="+odds71);
        System.out.println("验证结果，概率相加之和为"+check);
    }
 
    private static BigInteger getOdds(Integer n,Integer k) {
        BigInteger lotteryOdds = BigInteger.valueOf(1);
        for(int i = 1; i<=k;i++) {
            lotteryOdds = lotteryOdds.multiply(BigInteger.valueOf(n-i+1)).divide(BigInteger.valueOf(i));
        }
        return lotteryOdds;
    }
}

 结果：

run：
双色球中奖概率（6/33+1/16）：
一等奖（中6+1）中奖概率：1/17721088=0.00000006
二等奖（中6+0）：15/17721088=0.00000085
三等奖（中5+1）(3000元）中奖概率：162/17721088=0.00000914
四等奖（中5+0或4+1）(200元）中奖概率：7695/17721088=0.0004
五等奖（中4+0或3+1）(10元）中奖概率：137475/17721088=0.0078
六等奖（中2+1或1+1或0+1）(5元）中奖概率：1043640/17721088=0.0589
不中奖概率：16532100/17721088=0.9329
验证结果，概率相加之和为1.00001005
成功生成（总时间：0 秒）

 

祝大家中大奖，交好运！

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