# HDOJ/HDU 1133 Buy the Ticket(数论~卡特兰数~大数~)

Problem Description
The “Harry Potter and the Goblet of Fire” will be on show in the next few days. As a crazy fan of Harry Potter, you will go to the cinema and have the first sight, won’t you?

Suppose the cinema only has one ticket-office and the price for per-ticket is 50 dollars. The queue for buying the tickets is consisted of m + n persons (m persons each only has the 50-dollar bill and n persons each only has the 100-dollar bill).

Now the problem for you is to calculate the number of different ways of the queue that the buying process won’t be stopped from the first person till the last person.
Note: initially the ticket-office has no money.

The buying process will be stopped on the occasion that the ticket-office has no 50-dollar bill but the first person of the queue only has the 100-dollar bill.

Input
The input file contains several test cases. Each test case is made up of two integer numbers: m and n. It is terminated by m = n = 0. Otherwise, m, n <=100.

Output
For each test case, first print the test number (counting from 1) in one line, then output the number of different ways in another line.

Sample Input
3 0
3 1
3 3
0 0

Sample Output
Test #1:
6
Test #2:
18
Test #3:
180

m个人拿50，n个人拿1001、

2、现在我们假设拿50的人用‘0’表示，拿100的人用‘1’表示。 如果有这么一个序列0101101001001111。

http://blog.csdn.net/qq_26525215/article/details/51453493

import java.math.BigInteger;
import java.util.Scanner;

/**
* @author 陈浩翔
*
* 2016-5-19
*/
public class Main{
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int t=0;
while(sc.hasNext()){
int m =sc.nextInt();
int n =sc.nextInt();
if(n==0&&m==0){
return;
}
System.out.println("Test #"+(++t)+":");

if(n>m){
System.out.println(0);
continue;
}

BigInteger a = new BigInteger("1");

for(int i=2;i<=m+n;i++){
a=a.multiply(new BigInteger(""+i));
}
a=a.multiply(new BigInteger(""+(m-n+1)));
a=a.divide(new BigInteger(""+(m+1)));
System.out.println(a);
}
}
}


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