Train Problem II

 

 代码如下：

#include<iostream>  
#include <cstring>
 using  namespace std;
const int MOD = 10000;

int n;

int c[105][20];

int main()
{
    memset(c, 0, sizeof c);
    c[1][1] = 1;

    for(int i = 2; i <= 100; i ++ )
    {
        int rem = 0;
        for(int j = 1; j <= 17; j ++ )
        {
            c[i][j] = c[i - 1][j] * (4 * i - 2) + rem;
            rem = c[i][j] / MOD;
            c[i][j] %= MOD;
        }

        rem = 0;
        for(int j = 17; j >= 1; j -- )
        {
            c[i][j] += rem * MOD;
            rem = c[i][j] % (i + 1);
            c[i][j] /= (i + 1);
        }
    }

    while(scanf("%d", &n) !=EOF)
    {
        bool flag = false;
        for(int i = 17; i >= 1; i -- )
        {
            if(flag) printf("%04d", c[n][i]);
            else if(c[n][i])
            {
                printf("%d", c[n][i]);
                flag = true;
            }
        }
        printf("\n");
    }
    


    return  0 ;
}

参考：https://www.796t.com/content/1504328302.html

　　　https://zhuanlan.zhihu.com/p/97619085

　　　https://www.cnblogs.com/Morning-Glory/p/11747744.html