I guess this is correct.
來源:
亂彈
於
2009-03-04 17:50:00
[博客] [舊帖]
[給我悄悄話]
本文已被閱讀:次
Basically using Euler's formula, V-E+F=1, where F=2005.
Besides the four corners, every vertex is of degree at least 3, so we have 8+3(V-4) ≤ 2E. Combine these two, we get the answer.