BZOJ 4521 手机号码

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
long long l,r,dp[13][4][10][2][2][2],ret=0,bit[15];
void reset()
{
    for (long long i=0;i<=11;i++)
        for (long long j=0;j<=3;j++) 
            for (long long k=0;k<=9;k++)
                for (long long l=0;l<=1;l++)
                    for (long long a=0;a<=1;a++)
                        for (long long b=0;b<=1;b++)
                            dp[i][j][k][l][a][b]=-1;
}
void get_bit(long long x)
{
    ret=0;
    while (x) {bit[++ret]=x%10;x/=10;}
}
long long dfs(long long pos,long long cnt,long long num,long long f,long long f1,long long f2,bool flag)
{
    if (!pos) return f;
    if ((!flag) && (dp[pos][cnt][num][f][f1][f2]!=-1)) return dp[pos][cnt][num][f][f1][f2];
    long long ans=0,up=flag?bit[pos]:9,tc;
    for (long long i=0;i<=up;i++)
    {
        if ((i==4) && (f2)) continue;
        if ((i==8) && (f1)) continue;
        if (i==num) tc=min(cnt+1,3LL);else tc=1;
        ans+=dfs(pos-1,tc,i,f|(tc==3),f1|(i==4),f2|(i==8),flag&&(i==up));
    }
    if (!flag) dp[pos][cnt][num][f][f1][f2]=ans;
    return ans;
}
long long ask(long long x)
{
    get_bit(x);
    if (x==9999999999LL) return dfs(ret,1,0,0,0,0,1);
    else return dfs(ret,0,-1,0,0,0,1);
}
int main()
{
    scanf("%lld%lld",&l,&r);reset();
    printf("%lld\n",ask(r)-ask(l-1));
    return 0;
}