A - Train Problem II

最新推荐文章于 2025-09-07 20:32:33 发布

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原文链接：http://www.cnblogs.com/dulute/p/7272762.html

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#java

As we all know the Train Problem I, the boss of the Ignatius Train Station want to know if all the trains come in strict-increasing order, how many orders that all the trains can get out of the railway.

InputThe input contains several test cases. Each test cases consists of a number N(1<=N<=100). The input is terminated by the end of file.
OutputFor each test case, you should output how many ways that all the trains can get out of the railway.
Sample Input

Sample Output

Hint

The result will be very large, so you may not process it by 32-bit integers.

        卡兰特数 JAVA 好 max！

 1 import java.util.*;
 2 import java.math.*;
 3 public class Main 
 4 {
 5  public static BigInteger TM;
 6  public static void main(String[] args)
 7  {
 8   Scanner sc=new Scanner(System.in);
 9   while(sc.hasNext())
10   {
11    int n=sc.nextInt();
12    if(n==-1)
13        break;
14    int a,b;
15    TM=BigInteger.ONE;
16    TM=TM.multiply(BigInteger.valueOf(2));
17    if(n==1)
18    {
19        System.out.println(1);
20        continue;
21    }
22    if(n==2)
23    {
24        System.out.println(2);
25        continue;
26    }
27    for(int i=3;i<=n;i++)
28    {
29        a=4*i-2;
30        b=i+1;
31     TM=TM.multiply(BigInteger.valueOf(a));
32     TM=TM.divide(BigInteger.valueOf(b));
33    
34    }
35    System.out.println(TM);
36   }
37  }
38 }