Stockbroker Grapevine http://acm.pku.edu.cn/JudgeOnline/problem?id=1125
Invitation Cards http://acm.pku.edu.cn/JudgeOnline/problem?id=1511
Currency Exchange http://acm.pku.edu.cn/JudgeOnline/problem?id=1860
MPI Maelstrom http://acm.pku.edu.cn/JudgeOnline/problem?id=1502
Heavy Transportation http://acm.pku.edu.cn/JudgeOnline/problem?id=1797
Arbitrage http://acm.hdu.edu.cn/showproblem.php?pid=1217
Frogger http://acm.pku.edu.cn/JudgeOnline/problem?id=2253
Til the Cows Come Home http://acm.pku.edu.cn/JudgeOnline/problem?id=2387
Wormholes http://acm.pku.edu.cn/JudgeOnline/problem?id=3259
Silver Cow Party http://acm.pku.edu.cn/JudgeOnline/problem?id=3268
Big Christmas Tree http://acm.pku.edu.cn/JudgeOnline/problem?id=3013
Skiing http://acm.pku.edu.cn/JudgeOnline/problem?id=3037
Candies http://acm.pku.edu.cn/JudgeOnline/problem?id=3159
Cow Hurdles http://acm.pku.edu.cn/JudgeOnline/problem?id=3615
Cow Contest http://acm.pku.edu.cn/JudgeOnline/problem?id=3660
