There are n people labelled 1 to n, and a list dislikes of pairs [a, b] meaning person a and person b do not get along. Return true if everyone can be split into two groups so that no two people who dislike each other are in the same group.
- Dislike goes both ways: the pair
[a, b] applies to both of them - People who dislike nobody can go in either group. The groups can be of any size, and one may be empty
- The graph can be disconnected, so one search from person 1 is not enough
- A pair like
[3, 3] cannot be satisfied