Archive 2015 May-11th UVa 10799 - OOPS! They did it Again... 數學觀察 2014 Dec-27th UVa 1482 - Playing With Stones SG博弈觀察 Dec-14th UVa 12866 - Combination 數學觀察遞推 Nov-22nd UVa 12865 - Volume Control 數學窮舉觀察 May-19th UVa 12716 - GCD XOR 觀察