学步园

挺不错的一道按位DP

/*
ID: xinming2
PROG: stall4
LANG: C++
*/
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <cstring>
#include <map>
#include <string>
#include <stack>
#include <cctype>
#include <vector>
#include <queue>
#include <set>
#include <utility>
#include <cassert>
using namespace std;
///#define Online_Judge
#define outstars cout << "***********************" << endl;
#define clr(a,b) memset(a,b,sizeof(a))
#define lson l , mid  , rt << 1
#define rson mid + 1 , r , rt << 1 | 1
#define mk make_pair
#define FOR(i , x , n) for(int i = (x) ; i < (n) ; i++)
#define FORR(i , x , n) for(int i = (x) ; i <= (n) ; i++)
#define REP(i , x , n) for(int i = (x) ; i > (n) ; i--)
#define REPP(i ,x , n) for(int i = (x) ; i >= (n) ; i--)
const int MAXN = 100000 + 50;
const int sigma_size = 26;
const long long LLMAX = 0x7fffffffffffffffLL;
const long long LLMIN = 0x8000000000000000LL;
const int INF = 0x7fffffff;
const int IMIN = 0x80000000;
#define eps 1e-8
const int MOD = (int)1e9 + 7;
typedef long long LL;
const double PI = acos(-1.0);

typedef pair<int , int> pi;
#define Bug(s) cout << "s = " << s << endl;
///#pragma comment(linker, "/STACK:102400000,102400000")
int dp[25][15] , digit[25];
int get(int t ,int i , int lastnum)
{
    if(t == 11)
    {
        if(i == 0)return 11;
        return i;
    }
    if(abs(i - lastnum) >= 2)return i;
    return -1;
}
int dfs(int len , int lastnum ,int t, bool fp)///fp表示是否为首位
{
    if(t == -1)return 0;
    if(!len)return 1;
    if(!fp && t >= 0 && dp[len][t] != -1)return dp[len][t];
    int res = 0;
    int maxi = fp ? digit[len] : 9;
    for(int i = 0 ; i <= maxi ; i++)
    {
        res += dfs(len - 1 , i , get(t , i , lastnum) ,fp && i == maxi);
    }
    if(!fp)dp[len][t] = res;
    return res;
}
int f(int n)
{
    int len = 0;
    while(n)
    {
        digit[++len] = n % 10;
        n /= 10;
    }
    return dfs(len , 0 , 11 ,    true);
}
int main()
{
    int a , b;
    clr(dp , -1);
    while(~scanf("%d%d" , &a , &b))
    {
        printf("%d\n" , f(b) - f(a - 1));
    }
    return 0;
}