题解 | #幸运数字#

#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>

using namespace std;
using ll = long long;

vector<ll> lucky_numbers;

void generate_lucky_numbers() {
    queue<ll> q;
    q.push(6);
    q.push(8);
    lucky_numbers.push_back(6);
    lucky_numbers.push_back(8);

    while (!q.empty()) {
        ll current = q.front();
        q.pop();

        ll next6 = current * 10 + 6;
        if (next6 <= 1000000000) {
            lucky_numbers.push_back(next6);
            q.push(next6);
        }

        ll next8 = current * 10 + 8;
        if (next8 <= 1000000000) {
            lucky_numbers.push_back(next8);
            q.push(next8);
        }
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    generate_lucky_numbers();
    
    int a, b;
    while (cin >> a >> b) {
        int count = 0;
        for (ll num : lucky_numbers) {
            if (num >= a && num <= b) {
                count++;
            }
        }
        cout << count << endl;
    }

    return 0;
}

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;

public class Main {
    static ArrayList<Long> luckyNumbers = new ArrayList<>();

    public static void generateLuckyNumbers() {
        Queue<Long> queue = new LinkedList<>();
        queue.add(6L);
        queue.add(8L);
        luckyNumbers.add(6L);
        luckyNumbers.add(8L);

        while (!queue.isEmpty()) {
            long current = queue.poll();

            long next6 = current * 10 + 6;
            if (next6 <= 1000000000L) {
                luckyNumbers.add(next6);
                queue.add(next6);
            }

            long next8 = current * 10 + 8;
            if (next8 <= 1000000000L) {
                luckyNumbers.add(next8);
                queue.add(next8);
            }
        }
    }

    public static void main(String[] args) {
        generateLuckyNumbers();
        Scanner sc = new Scanner(System.in);
        while (sc.hasNextInt()) {
            int a = sc.nextInt();
            int b = sc.nextInt();

            int count = 0;
            for (long num : luckyNumbers) {
                if (num >= a && num <= b) {
                    count++;
                }
            }
            System.out.println(count);
        }
    }
}

import sys
from collections import deque

def generate_lucky_numbers():
    """
    生成所有小于等于 10^9 的幸运数
    """
    lucky_nums = []
    q = deque([6, 8])
    lucky_nums.extend([6, 8])

    while q:
        current = q.popleft()
        
        next6 = current * 10 + 6
        if next6 <= 1000000000:
            lucky_nums.append(next6)
            q.append(next6)
            
        next8 = current * 10 + 8
        if next8 <= 1000000000:
            lucky_nums.append(next8)
            q.append(next8)
            
    return lucky_nums

LUCKY_NUMBERS = generate_lucky_numbers()

def solve():
    for line in sys.stdin:
        try:
            a, b = map(int, line.strip().split())
            count = 0
            for num in LUCKY_NUMBERS:
                if a <= num <= b:
                    count += 1
            print(count)
        except (IOError, ValueError):
            continue

solve()