Ural 1353. Milliard Vasya's Function 暴搜

1353. Milliard Vasya's Function

Time limit: 1.0 second

Memory limit: 64 MB

Vasya is the beginning mathematician. He decided to make an important contribution to the science and to become famous all over the world. But how can he do that if the most interesting facts such as
Pythagor’s theorem are already proved? Correct! He is to think out something his own, original. So he thought out the Theory of Vasya’s Functions. Vasya’s Functions (VF) are rather simple: the value of the Nth VF
in the point S is an amount of integers from 1 to N that have the sum of digitsS. You seem to be great programmers, so Vasya gave you a task to find the milliard VF value (i.e. the VF with N = 109)
because Vasya himself won’t cope with the task. Can you solve the problem?

Input

Integer S (1 ≤ S ≤ 81).

Output

The milliard VF value in the point S.

Sample

input	output
1	10

Problem Author: Denis Musin

Problem Source: USU Junior Championship March'2005
求1到10^9中各位数字之和为s的数

#include <iostream>
using namespace std;
int a[82];
int main()
{
    int i,j,k;
    a[0]=1;
    for(i=1; i<=9; i++)
        for(j=9*i; j>=1; j--)
            for(k=1; k<=9; k++)
            {
                if(k>j) break;
                a[j]+=a[j-k];
            }
    a[1]++;
    cin>>i;
    cout<<a[i]<<endl;
}