bitset commonly used functions and operators

bitset is an array, but each element is a bit, is 0 or 1, which greatly saves space; 

 

Specific usage can be found in:

https://www.cnblogs.com/RabbitHu/p/bitset.html

 

example:

Round # 561 codeforces (Div. 2)  E title

http://codeforces.com/contest/1166/problem/E