hdu 3555 Bomb

//第一个数位dp，由于别人的看不懂，然后自己还是摸索出来了，虽然写得比较麻烦，思路还是清楚的，dfs枚举每种情况就好了，要记忆化搜索，不然会超时，这题得用__int64

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int num[22];
__int64 dp[22][10][2];
int l;
__int64 dfs(int i,int j,bool find,bool flag)
{

          if(i==l&&find)return 1;
          if(i==l||j<0)return 0;
          if(!flag&&dp[i][j][find]!=-1)return dp[i][j][find];
         if(find)
         {
                if(!flag)return  dp[i][j][find]=10*dfs(i+1,0,1,0);
                return num[i]*dfs(i+1,0,1,0)+dfs(i+1,0,1,1);
         }
         if(!flag)
         {
            if(j==4)return  dp[i][j][find]=dfs(i+1,9,1,0)+dfs(i+1,4,0,0)+8*dfs(i+1,0,0,0);
            return  dp[i][j][find]=dfs(i+1,4,0,0)+9*dfs(i+1,0,0,0);
         }
        if(j==4&&num[i]==9)return dfs(i+1,9,1,1)+dfs(i+1,4,0,0)+8*dfs(i+1,0,0,0);
        if(num[i]==4)return dfs(i+1,4,0,1)+4*dfs(i+1,0,0,0);
        if(num[i]>4) return  dfs(i+1,4,0,0)+dfs(i+1,0,0,1)+(num[i]-1)*dfs(i+1,0,0,0);
        return dfs(i+1,0,0,1)+num[i]*dfs(i+1,0,0,0);
}
int main()
{
   __int64 n;int t;scanf("%d",&t);
   while(t--)
   {
         scanf("%I64d",&n);
         int k=0;
         while(n)
         {
              num[k++]=n%10;
              n/=10;
         }
         l=k;
         memset(dp,-1,sizeof(dp));
         for(int i=0;i<l/2;i++)swap(num[i],num[l-1-i]);
         printf("%I64d\n",dfs(0,0,0,1));
   }
   return 0;
}