View Code of Problem 18

#include<stdio.h>
int main()
{
	int n;int a[10000]={0},k=0; 
	for(int i=0;i<1000;i++)
	{
		a[i]=a[i-1]+k;
		if(i%2==0)
		{
			k++;
		}
	}
	while(scanf("%d",&n)!=EOF)
	{
		printf("%d\n",a[n]);
		
	}
	return 0; 
}