摘要：
Problem Description The counter-terrorists found a time bomb in the dust. But this time the terrorists improve on the time bomb. The number sequence o 阅读全文
摘要：
Description A straight dirt road connects two fields on FJ's farm, but it changes elevation more than FJ would like. His cows do not mind climbing up 阅读全文
摘要：
A group of contest writers have written n problems and want to use k of them in an upcoming contest. Each problem has a difficulty level. A contest is 阅读全文