hdu 2089 数位dp

数位dp  #1

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

int a[20] ;
int dp[20][2] ;

int dfs( int pos , int pre ,int sta , bool limit){
    if( pos <= -1) return 1 ;
    if( !limit && dp[pos][sta] != -1 ) return dp[pos][sta] ;

    int up = limit ? a[pos] : 9 ;
    int temp = 0 ;
    for( int i = 0 ; i <= up ; i ++ ){
        if( pre == 6 && i == 2) continue ;
        if( i == 4 ) continue ;
        temp += dfs(pos-1 , i , i==6 , limit && i==a[pos]);
    }
    if( !limit ) dp[pos][sta] = temp ;
    return temp ;
}

int solve( int x ){
    int pos = 0 ;
    while( x ){
        a[pos ++] = x % 10 ;
        x /= 10 ;
    }
    int ans = dfs(pos - 1 , -1 , 0 , true ) ;
    return ans ;
}

int main(){
    int n , m   ;
    while( ~ scanf("%d %d",&n , &m)  ){
        memset( dp , -1 , sizeof( dp )) ;
        if( !n && !m) break ;
        //for( int i = 0 ; i <= N ; i ++ ) G[i].clear() ;
        //memset( centroid , 0 , sizeof( centroid )) , memset(subtree_size , 0 , sizeof(subtree_size)) ;
        printf("%d\n" , solve(m) - solve(n-1));
    }
    return 0 ;

}