In graph theory, a graceful labeling of a graph with
N edges is a labeling of its vertices with some subset of the integers between 0 and
N , such that no two vertices share a label, and each edge is uniquely identified by the absolute difference between its endpoints.
A unproven conjecture in graph theory is the Graceful Tree conjecture or Ringel–Kotzig conjecture, which hypothesizes that all trees are graceful. Find a graceful labeling of this larger tree.
import Html exposing (text) import Maybe type Graph a = (List a, Edges a) g92 = Graph ([1..14], [(1,6),(2,6),(3,6),(4,6),(5,6),(5,7),(5,8),(8,9),(5,10),(10,11),(11,12),(11,13),(13,14)]) graceful : Graph a -> Maybe (Graph Int) graceful g = -- your implementation here main = case graceful g92 of Just a -> text (toString a) Nothing -> text "Alert the media! You have found and exception of the Graceful Tree conjecture."