[newSolution]Who can add 1 more problem of LeetCode 840

[LetMeFly666]

By Github Actions | 840.矩阵中的幻方 | 2025-12-30

[1problem1day]

Set the project status to based on the solving label.
🕒 Time (Beijing, UTC+8): 2025/12/30 00:21:18
🤖 Triggered by 1problem1day Bot according to action file

[1problem1day]

This issue was automatically added to the project.
🕒 Time (Beijing, UTC+8): 2025/12/30 00:21:19
🤖 Triggered by 1problem1day Bot according to action file

[LetMeFly666]

hello #1292 you are not alone now(/again).

[1problem1day]

Set the project status to In Progress based on the solving label.
🕒 Time (Beijing, UTC+8): 2025/12/30 13:14:30
🤖 Triggered by 1problem1day Bot according to action file