var i,n,k,m,j,MaxSum,t:word;
    s,c:longint;
function Dig_sum(x:word):word;
var res:word;
begin
  res:=0;
  while (x>0) do
   begin
     res:=res+(x mod 10);
     x:=x div 10
   end;
  Dig_sum:=res;
end;
begin
 readln(n);
 k:=1; t:=(n div 2);
 for i:=1 to t do k:=k*10; dec(k);
 MaxSum:=9*t;
 s:=0;
 for i:=0 to MaxSum do
  begin
    c:=0;
    for j:=0 to k do
           begin
             if Dig_sum(j)=i then inc(c);
           end;
    s:=s+c*c;
  end;
 if (n mod 2)=1 then s:=s*10;
 writeln(s);
 {Ukraine,Khmelnitsky State University}
end.

Edited by author 27.07.2004 21:14

 We worked exactly the same time! :-)

And i have 0.015 :)

Can you explain your codes?

My code:



import java.util.Scanner;
import java.io.IOException;
 public class Lucky{
  public static void main(String[] args)throws IOException{
   Scanner sc=new Scanner(System.in);
   int n=sc.nextInt();
   int[] m=new int[37];
   int k=0,l=0,f=(int)Math.pow(10,n/2)-1,f1=n/2*9,luk=0,n1=n/2;
   long s=0;
   while(l<=f){
    k=0;
     luk=l;
     for(int i=1;i<=n1;i++){
      k+=(luk%10);
      luk/=10;
     }
    m[k]+=1;
    l++;
   }
   for(int i=0;i<=f1;i++)
    s+=m[i]*m[i];
   System.out.println(s);
  }
 }

import java.io.*;
import java.util.Arrays;
import java.math.BigInteger;

public class Main {
    public static void main(String[] args)
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        try
        {
            //BufferedReader br = new BufferedReader(new FileReader("/Users/Mac/IdeaProjects/text.txt"));

            int n = Integer.parseInt(br.readLine());
            n/=2;
            int k_m = 9*n;
            long s=0;
            for (int k = 0;k<=k_m;k++)
            {
            if (k==0)
            {
                s+=1;
                continue;
            }
            long[][] a = new long[n+1][k+1];
            a[n][k] = 1;
            for (int i=n-1;i>=0;i--)
            {
                for (int j=k;j>=0;j--)
                {
                    for(int y=0;y<=9 && j+y<=k;y++)
                    {
                        a[i][j] += a[i+1][j+y];
                    }
                }
            }
            s+=a[0][0]*a[0][0];
            }
            System.out.println(s);
        }
        catch (IOException e)
        {
            return;
        }
    }
}

My code on C#

using System;
//using System.Text;
//using System.Globalization;
//using System.Threading;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main()
        {
            //Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture;
            int n = int.Parse(Console.ReadLine().Trim());
            //string[] input = Console.ReadLine().Split(new char[]{' ','\t','\r','\n'},
            //                                           StringSplitOptions.RemoveEmptyEntries);
            int count = 0;
            n /= 2;
            for (int sum = 0; sum <= 9 * n; sum++)
            {
                int k = K(sum, n);
                count += k * k;
            }
            Console.WriteLine(count);
            Console.ReadLine();
        }
        static int K(int sum, int n)
        {
            int[] m = new int[sum + 1];
            for (int i = 0; i <= sum; i++)
                if (i > 9) m[i] = 0; else m[i] = 1;
            for (int j = 1; j < n; j++)
            {
                for (int i = sum; i >= 0; i--)
                {
                    int zz = 0;
                    if (i > 9) zz = i - 9;
                    for (int z = zz; z < i; z++) m[i] += m[z];
                }
            }
            return m[sum];
        }
    }
}

I find that there is fewer people using RUBY to solve problem.
So it makes me list my solution, partly ( for the 4|4 situation :) )
------

Sum = Array.new(37,0)
"0000".upto("9999").each {|e|
    temp = 0
    e.each_char { |c|
      temp += c.to_f
    }
    Sum[temp] += 1
}
total = 0
puts Sum.map { |e| total += e*e}