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[][],ret=,bit[];
void get_table()
{
    for (int i=;i<=;i++) dp[][i]=;
    for (int i=;i<=;i++) dp[][i]=;
    for (int i=;i<=;i++)
        for (int j=;j<=;j++)
            for (int k=;k<=;k++)
                if (j>=k*(<<(i-))) dp[i][j]+=dp[i-][j-k*(<<(i-))];
    for (int i=;i<=;i++)
        for (int j=;j<=;j++)
            dp[i][j]+=dp[i][j-];
}
void get_bit(int x)
{
    ret=;
    while (x) {bit[++ret]=x%;x/=;}
}
int f(int x)
{
    get_bit(x);int ans=;
    for (int i=ret;i>=;i--) ans=(ans<<)+bit[i];
    return ans;
}
int dfs(int pos,int ret)
{
    if (!pos) return ;
    int i,ans=;
    for (i=;i<bit[pos];i++)
    {
        if (ret>=i*(<<(pos-)))
            ans+=dp[pos-][ret-i*(<<(pos-))];
        else break;
    }
    if (i!=bit[pos]) return ans;
    if (ret>=bit[pos]*(<<(pos-))) ans+=dfs(pos-,ret-bit[pos]*(<<(pos-)));
    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=;i<=t;i++)
    {
        scanf("%d%d",&a,&b);
        work(i);
    }
    return ;
}