答案：

import java.util.ArrayList;import java.util.List;public class Solution{    public static void main(String[] args){        int[][] matix = {
   {1,2},{0,3}};        clearZero(matix,2);        System.out.println(matix[0][1]);    }    public static int[][] clearZero(int[][] matrix, int n){        int high = matrix.length;        int wide = matrix.length;        if(high == 0) return matrix;        List
     
       listRow = new ArrayList();        List
      
        listCol = new ArrayList();        for(int i = 0; i < wide; i++){            for(int j = 0; j < high; j++){                if(matrix[i][j] == 0){                    listRow.add(i);                    listCol.add(j);                }            }        }        for(int tmp : listRow){            for(int j = 0; j < high; j++){                matrix[tmp][j] = 0;            }        }        for(int tmp : listCol){            for(int i = 0; i < wide; i++){                matrix[i][tmp] = 0;            }        }        return matrix;    }