[动态规划][数位dp]Bomb

#include <iostream>
#include<cstdio>
typedef long long ll;
using namespace std;

ll dp[15][2];
ll digit[15];

ll dfs(ll len,bool last_4,bool limit){
  if(len==0) return 1;
  if(!limit && dp[len][last_4]) return dp[len][last_4];
  ll sum=0;
  for(ll i=0;i<=(limit?digit[len]:9);i++){
    if(!(last_4&&i==9)) sum+=dfs(len-1,i==4,limit&&i==digit[len]);
  }
  if(!limit) dp[len][last_4]=sum;
  return sum;
}

ll solve(ll x){
  digit[0]=0;
  while(x){
    digit[++digit[0]]=x%10;
    x/=10;
  }
  return dfs(digit[0],false,true);
}

int main()
{
    ll t;scanf("%lld",&t);
    while(t--){
        ll n;scanf("%lld",&n);
        printf("%lld\n",n-(solve(n)-1));
    }
    return 0;
}