hdu3555 Bomb(数位dp)

hdu3555

题目

思路

代码

#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<queue>
#include<algorithm>
#include<stack>

using namespace std;

typedef  long long ll;

ll dp[40][2];
int dis[30];

ll dfs(int len,int pre,int lim)
{
if(len<0)
return 1;
if(!lim&&dp[len][pre]!=-1) return dp[len][pre];
ll res=0;
int u=lim?dis[len]:9;
for(int s=0; s<=u; s++)
{
if(!(pre&&s==9))
{
res+=dfs(len-1,s==4,lim&&s==u);
}
}
if(!lim) return dp[len][pre]=res;
return res;
}

ll n;

ll solve(ll u)
{
int len=0;
while(u)
{
dis[len++]=u%10;
u/=10;
}
return dfs(len-1,0,1);
}

int main()
{
int T;
scanf("%I64d",&T);
while(T--)
{
scanf("%I64d",&n);
memset(dp,-1,sizeof(dp));
printf("%I64d\n",n-(solve(n)-1));
}
return 0;
}