题解 | #挑7#

Java 实现 挑7 算法

import java.util.*;
import java.lang.*;

public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()) {
           int n = sc.nextInt();
           List<Integer> list = new ArrayList<Integer>();
           String str = "";
           for(int i = 1 ;i<=n;i++) {
               str = String.valueOf(i);
               if(str.contains("7") || i%7 == 0){
                   list.add(i);
               } 
            }
            System.out.println(list.size());
        }     
    }
}