View Code of Problem 610

#include<stdio.h>
int main()
{
	int a[30]={0};
	a[0] = 1;
	a[1] = 1;
	a[2] = 2;
	a[3] = 5;
	int n,i,j = 0;
	int sum = 0;
	while(scanf("%d",&n)!=EOF)
	{
		if(n>=4)
		{
			for(i =4;i<=n;i++)
			{
				sum = 0;
				for(j  = 0;j<i;j++) 
				{
					sum =sum + a[j]*a[i-j-1];
				}
				a[i] = sum;
			}
			printf("%d\n",a[n]);
		}
		else
			printf("%d\n",a[n]);
	}
	return 0;
 }