摘要：
You are given an array aa of length nn and array bb of length mm both consisting of only integers 00 and 11 . Consider a matrix cc of size n×mn×m form 阅读全文
摘要：
You are given an array aa consisting of nn positive integers. Find a non-empty subset of its elements such that their sum is even (i.e. divisible by 2 阅读全文
摘要：
A bracketed sequence is called correct (regular) if by inserting "+" and "1" you can get a well-formed mathematical expression from it. For example, s 阅读全文