这个其实挺蠢的, 老师又说你hardcode啦.
[cc lang="java" line\_numbers="true"]
public class LotteryQuestion
{
private static int start2generateBalls()
{
return C(33, 6) * C(16, 1);// 33选6,16选1
}
static int C(int k, int n)
{
int rs = 1;
for (int i = 1; i <= n; i++)
rs = rs * (k - i + 1) / i;
return rs;
}
static int Bingo(int type)
{
int fenmu;
switch (type)
{
case 1:
fenmu = 1;
break;
case 2:
fenmu = 15;
break;
case 3:
fenmu = 6 * 27;
break;
case 4:
fenmu = C(6, 5) * C(27, 1) * C(15, 1) + C(6, 4) * C(27, 2);
break;
case 5:
fenmu = C(6, 4) * C(27, 2) * C(15, 1) + C(6, 3) * C(27, 3);
break;
case 6:
fenmu = C(6, 2) * C(27, 4) + C(6, 1) * C(27, 5) + C(27, 6);
break;
default:
fenmu = 0;
break;
}
return start2generateBalls() / fenmu;
}
public static void main(String[] args)
{
System.out.println("[一等奖] -> [1/" + Bingo(1) + "]");
System.out.println("[二奖奖] -> [2/" + Bingo(2) + "]");
System.out.println("[三等奖] -> [1/" + Bingo(3) + "]");
System.out.println("[四等奖] -> [1/" + Bingo(4) + "]");
System.out.println("[五等奖] -> [1/" + Bingo(5) + "]");
System.out.println("[末等奖] -> [1/" + Bingo(6) + "]");
}
}[/cc]

root@11th:/home# java LotteryQuestion
[一等奖] -> [1/17721088]
[二奖奖] -> [2/1181405]
[三等奖] -> [1/109389]
[四等奖] -> [1/2302]
[五等奖] -> [1/128]
[末等奖] -> [1/16]