# Rosalind: TREE — Completing a Tree
# https://rosalind.info/problems/tree/
#
# Given: A positive integer n and an adjacency list of a graph on n nodes that
# forms a forest.
# Return: The minimum number of edges needed to produce a tree.

let n = 10
let edge_list = [[1,2],[2,8],[4,10],[5,9],[6,10],[7,9]]

# A tree on n nodes has exactly n-1 edges, and a forest with e edges has
# n-e components — so joining them needs (n-1)-e more.
let result = (n - 1) - len(edge_list)

println("Result:   " + str(result))
println("Expected: 3")

fn test_tree_edges_to_add() {
    assert result == 3, "TREE: got " + str(result)
}