201912-1 报数 Java

思路：
String.valueOf(int i) : 将 int 变量 i 转换成字符串
String.contains()用于判断字符串是否包含子字符串

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int a[] = new int[4];
        for(int i = 0; i < n; i++) {
            if((i+1) % 7 == 0 || String.valueOf(i+1).contains("7")) {
                a[i%4] ++;
                n++;
            }
        }
		sc.close();
        for(int i = 0; i < 4; i++) {
            System.out.println(a[i]);
        }
	}
}