hdu 2089 数位dp入门

HDU 2089

题意：中文题

思路：数位dp入门题

AC代码：

#include "iostream"
#include "string.h"
#include "stack"
#include "queue"
#include "string"
#include "vector"
#include "set"
#include "map"
#include "algorithm"
#include "stdio.h"
#include "math.h"
#pragma comment(linker, "/STACK:102400000,102400000")
#define ll long long
#define endl ("
")
#define bug(x) cout<<x<<" "<<"UUUUU"<<endl;
#define mem(a,x) memset(a,x,sizeof(a))
#define mp(x,y) make_pair(x,y)
#define pb(x) push_back(x)
#define ft (frist)
#define sd (second)
#define lrt (rt<<1)
#define rrt (rt<<1|1)
using namespace std;
const long long INF = 1e18+1LL;
const int inf = 1e9+1e8;
const int N=1e3+100;
const ll mod=1e9+7;

int bit[20],dp[20][2];

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

int solve(int x){
    int t=0;
    while(x>0){
        bit[++t]=x%10;
        x/=10;
    }
    return dfs(t, -1, 0, 1);
}

int main(){
    ll l,r; mem(dp,-1);
    while(cin>>l>>r && l&&r){
        cout<<solve(r)-solve(l-1)<<endl;
    }
    return 0;
}