HDU 2089 不要 62

不要   4 和 62 

#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<cstring>
using namespace std;

int arr[20],dp[20][3];

int pow( int num )
{
    int ans = 1;
    for( int i = 0; i < num;i++ )
    ans*=10;
    return ans;
}
int DFS( int pos,int flag, int end )
{
    if( pos == -1 ){return (flag == 2);}
    if( !end && dp[pos][flag] != -1 ) return dp[pos][flag];
    if( !end && flag == 2 )           return dp[pos][flag] = pow(pos+1);
    int limit = end?arr[pos]:9,ans = 0;
    for( int i = 0; i <= limit; i++ )
    {
        int tab = flag;
        if( flag == 1 && i == 2 )tab = 2;
        else if( i == 4 ) tab = 2;
             else if( flag == 1 && i != 6 ) tab = 0;
                  else if( flag != 2 && i == 6 ) tab = 1;
        ans += DFS( pos-1,tab,end&&(i==limit) );
    }
    if( !end ) dp[pos][flag] = ans;
    return ans;
}
int work( int num )
{
    int k = 0;
    while( num )
    {
        arr[k++] = num%10;
        num = num/10;
    }
    memset( dp,-1,sizeof(dp) );
    return DFS( k-1,0,1 );
}
int main( )
{
    int N,M;
    while( scanf("%d%d",&N,&M) != EOF )
    {
        if( N == 0 && M == 0 ) break;
        printf("%d\n",M - N + 1 - (work(M) - work(N-1)));
    }
    return 0;
}