Python项目：二维N×N网格绘制对角X形状功能实现语法问题

实现代码 #

def mark_the_spot(grid: list, sign: str) -> list:
    n = len(grid)
    for row_idx in range(n):
        # 填充主对角线位置
        grid[row_idx][row_idx] = sign
        # 填充副对角线位置
        grid[row_idx][n - 1 - row_idx] = sign
    return grid

实现逻辑 #

• 先获取网格的边长n，题目已限定输入为N×N的正奇数网格，无需做额外参数校验
• 逐行遍历网格：
  • 主对角线的坐标规则为行号等于列号，直接替换为指定字符
  • 副对角线的坐标规则为列号 = 边长-1 - 行号，直接替换为指定字符
• 重复赋值中间交点位置不会影响最终结果，无需额外做去重判断，代码更简洁易读

验证示例 #

你可以用题目给出的测试用例直接验证，返回结果和示例完全一致：

# 3x3网格测试
grid_3 = [[" ", " ", " "], [" ", " ", " "], [" ", " ", " "]]
result_3 = mark_the_spot(grid_3, 'X')
for row in result_3:
    print(row)
# 输出：
# ['X', ' ', 'X']
# [' ', 'X', ' ']
# ['X', ' ', 'X']

# 7x7网格测试
grid_7 = [[" "]*7 for _ in range(7)]
result_7 = mark_the_spot(grid_7, '#')
for row in result_7:
    print(row)
# 输出和题目给出的7x7示例完全一致

内容的提问来源于stack exchange，提问作者Ablay Kabash