摘要：
Problem Description soda has a set S with n integers {1,2,…,n}. A set is called key set if the sum of integers in the set is an even number. He wants 阅读全文
摘要：
Each soda has some candies in their hand. And they want to make the number of candies the same by doing some taking and giving operations. More specif 阅读全文