java计算机器人的运动范围

public class Solution {
 public int movingCount(int threshold, int rows, int cols)
 {
  if(threshold<0 || rows<=0 || cols<=0){
   return 0;
  }
  int count = 0;
  boolean[] flag = new boolean[rows*cols];
  for(int i=0; i<rows*cols; i++){
   flag[i] = true;
  }
  count = Moving(threshold, 0, 0, rows, cols, flag);
  return count;
 }

 public int Moving(int t, int row, int col, int rows, int cols, boolean[] flag){
  int count = 0;
  if(isAllow(t, row, col, rows, cols, flag)){
   flag[row*cols+col] = false;
   count = 1+Moving(t, row-1, col, rows, cols, flag)+Moving(t, row, col-1, rows, cols, flag)+Moving(t, row+1, col, rows, cols, flag)+Moving(t, row, col+1, rows, cols, flag);
  }
  return count;
 }

 //计算坐标的位数和，返回与threshold的比较结果
 public boolean isAllow(int t, int row, int col, int rows, int cols, boolean[] flag){
  if(row>rows ||row<0 || col>cols || col<0 || row*cols+col>rows*cols-1|| flag[row*cols+col]==false){
   return false;
  }
  int sum = 0;
  char[] chs = (row+"").toCharArray();
  char[] chs1= (col+"").toCharArray();
  for(char ch: chs){
   sum += Character.getNumericValue(ch);
  }
  for(char ch1: chs1){
   sum += Character.getNumericValue(ch1);
  }
  return sum<=t;
 }
}