摘要：
Robert is a gymnastics coach. Unfortunately, he got four gymnastics beginners to attend the coming competition. Since the competition has a nice award 阅读全文
摘要：
Problem Description Bob has N balls and A boxes. He numbers the balls from 0 to N-1, and numbers the boxes from 0 to A-1. To find the balls easily, he puts the ball numbered x into the box numbered ... 阅读全文
摘要：
There is a straight highway with N storages alongside it labeled by 1,2,3,...,N. Bob asks you to paint all storages with two colors: red and blue. Eac 阅读全文
摘要：
In Zhejiang University, there are N different courses labeled from 1 to N. Each course has its own time slot during the week. We can represent the tim 阅读全文