蓝桥杯 基础练习 字母图形

请问这个代码是有哪种情况没考虑到的吗，提交后显示部分测试样例没通过

import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        char[][] arr = new char[n][m];
        for(int j=0; j<m; j++) {
            //第一行
            arr[0][j] = ((char) (j + (int) 'A'));
            System.out.print(arr[0][j]);
        }
        System.out.println();
        for(int i = 1;i<n; i++) {
            //第一列
            arr[i][0] = ((char) (i + (int) 'A'));
            System.out.print(arr[i][0]);
            for(int j = 1;j<m; j++) {
                arr[i][j] = arr[i-1][j-1];
                System.out.print(arr[i][j]);
            }
            System.out.println();
        }
 
    }
}

public static void main(String[] args)
{
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    int m = sc.nextInt();
    for (int i = 0; i < n; i++)
    {
        String s = "";
        for (int j = 0; j < m; j++)
        {
            char a= (char) ('A' + Math.abs(i - j));
            s = s + a;
        }
        System.out.println(s);
    }
}