HDU 4734 F(x)

这题可能非递归版好写？

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int t,a,b,dp[12][5000],ret=0,bit[12];
void get_table()
{
    for (int i=0;i<=9;i++) dp[1][i]=1;
    for (int i=0;i<=4599;i++) dp[0][i]=1;
    for (int i=2;i<=8;i++)
        for (int j=0;j<=4599;j++)
            for (int k=0;k<=9;k++)
                if (j>=k*(1<<(i-1))) dp[i][j]+=dp[i-1][j-k*(1<<(i-1))];
    for (int i=1;i<=8;i++)
        for (int j=1;j<=4599;j++)
            dp[i][j]+=dp[i][j-1];
}
void get_bit(int x)
{
    ret=0;
    while (x) {bit[++ret]=x%10;x/=10;}
}
int f(int x)
{
    get_bit(x);int ans=0;
    for (int i=ret;i>=1;i--) ans=(ans<<1)+bit[i];
    return ans;
}
int dfs(int pos,int ret)
{
    if (!pos) return 1;
    int i,ans=0;
    for (i=0;i<bit[pos];i++)
    {
        if (ret>=i*(1<<(pos-1)))
            ans+=dp[pos-1][ret-i*(1<<(pos-1))];
        else break;
    }
    if (i!=bit[pos]) return ans;
    if (ret>=bit[pos]*(1<<(pos-1))) ans+=dfs(pos-1,ret-bit[pos]*(1<<(pos-1)));
    return ans;
}
void work(int x)
{
    int ff=f(a);get_bit(b);
    printf("Case #%d: %d\n",x,dfs(ret,ff));
}
int main()
{
    scanf("%d",&t);get_table();    
    for (int i=1;i<=t;i++)
    {
        scanf("%d%d",&a,&b);
        work(i);
    }
    return 0;
}