Tournament Round-robin

Create a vector of rounds and their respective matches in a tournament, using the Round-robin algorithm.

Examples with numbers:

let rounds1 = round_robin((1..= 4).collect()); print!("{:?}", rounds1); Output: [[(1,4), (2,3)], [(1,3), (4,2)], [(1,2), (3,4)]]

Examples with strings:

let rounds2 = round_robin(vec!["a", "b", "c", "d"]); print!("{:?}", rounds2); Output: [[("a", "d"), ("b", "c")], [("a", "c"), ("d", "b")], [("a", "b"), ("c", "d")]]