Ural 1353 milliard Vasya's function (DP)

Subject address: Ural 1353

Define DP [I] [J], indicating that when the current number of digits is I, the sum of the numbers is J.

For the I-digit, it can always be seen as adding a 0 ~ after the front I-1 bit ~ 9, so the state transition equation is easy to come out:

DP [I] [J] = DP [I] [J] + dp [I] [J-1] + dp [I] [J-2] + ....... + dp [I] [j-9];

The final statistics are enough.

The Code is as follows:

#include <iostream>#include <cstdio>#include <string>#include <cstring>#include <stdlib.h>#include <math.h>#include <ctype.h>#include <queue>#include <map>#include <set>#include <algorithm>using namespace std;const int INF=0x3f3f3f3f;#define LL long longint dp[10][90];int main(){    int n, i, j, sum, s, k;    memset(dp,0,sizeof(dp));    for(i=1;i<=9;i++)        dp[1][i]=1;    for(i=2;i<=9;i++)    {        s=0;        for(j=1;j<=81;j++)        {            for(k=0;k<j&&k<=9;k++)            {                dp[i][j]+=dp[i-1][j-k];            }        }    }    while(scanf("%d",&n)!=EOF)    {        if(n==1)        {            puts("10");            continue ;        }        sum=0;        for(i=1;i<=9;i++)        {            sum+=dp[i][n];        }        printf("%d\n",sum);    }    return 0;}

Ural 1353 milliard Vasya's function (DP)