Java，0-9每个数有2021个，从数字0开始向后计算消耗数字的个数，直到0-9中有数字被用完。

package yang_day18_1;

public class day18_test2 {
    public static void main(String[] args) {
        int[] a={2021,2021,2021,2021,2021,2021,2021,2021,2021,2021};
        int num=0;
        for (int i = 0; i < 99999; i++) {
            String s="";
            s+=i;
            char[] c=s.toCharArray();
            for (int i1 = 0; i1 < c.length; i1++) {
                int j=c[i1];
                if(a[j-48]>0)
                    a[j-48]--;
                else{
                    System.out.println(i-1);
                    return;
                }
            }
        }


    }
}