HDU3555 Bomb[数位DP]

B - Bomb

#pragma comment(linker, "/STACK:102400000,102400000")
#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<string>
#include<algorithm>
#include<queue>
#include<stack>
#include<set>
#include<map>
#include<vector>
using namespace std;
typedef long long ll;
const int N=30;
ll dp
[3];
int num
;
ll dfs(int pos,int sta,bool limit)//sta 0前面没有4   1前面有4  2前面有49
{
if (pos==-1)
return sta==2;//前面是否有49
if (!limit && dp[pos][sta]!=-1)
return dp[pos][sta];
ll cnt=0;
int mx=limit?num[pos]:9;
for (int i=0 ; i<=mx ; ++i)
{
if ((sta==1 && i==9) || sta==2)
cnt+=dfs(pos-1,2,limit && i==num[pos]);
else
cnt+=dfs(pos-1,i==4,limit && i==num[pos]);
}
if (!limit)
dp[pos][sta]=cnt;
return cnt;
}
ll divi(ll n)
{
int pos=0;
while (n)
{
num[pos++]=n%10;
n/=10;
}
return dfs(pos-1,0,1);
}
int main()
{
int T;
scanf("%d",&T);
memset(dp,-1,sizeof(dp));
while (T--)
{
ll n;
scanf("%lld",&n);
printf("%lld\n",divi(n));
}
return 0;
}