统计数字,这个程序有什么问题吗?求大神public class Solution { int y=1; int x; int num; int z; int r; public int digitCounts(int k, int n) { int[] j = new int[n+1]; for(int p=0;p<n+1;p++) { j[p]=p; } for (;r<n+1;){ if (x<Math.pow(10,y)) { for (int o = 0; o <y; o++) { z = j[x] / ((int) Math.pow(10, o)) % 10; if (k == z) { num++; } } x++; r++; } else{y++;} } return num; }}