use v6-alpha;
use Test;
use v6;
use Test;
plan 1;

# P68 (**) Preorder and inorder sequences of binary trees
# 
# We consider binary trees with nodes that are identified by single lower-case
# letters, as in the example of problem P67.
# 
# a) Write predicates preorder/2 and inorder/2 that construct the preorder and
# inorder sequence of a given binary tree, respectively. The results should be
# atoms, e.g. 'abdecfg' for the preorder sequence of the example in problem P67.
# 
# b) Can you use preorder/2 from problem part a) in the reverse direction; i.e.
# given a preorder sequence, construct a corresponding tree? If not, make the
# necessary arrangements.
# 
# c) If both the preorder sequence and the inorder sequence of the nodes of a
# binary tree are given, then the tree is determined unambiguously. Write a
# predicate pre-in-tree/3 that does the job.
# 
# d) Solve problems a) to c) using difference lists. Cool! Use the predefined
# predicate time/1 to compare the solutions.
# 
# What happens if the same character appears in more than one node. Try for
# instance pre-in-tree(aba,baa,T).

if 1 {
    skip 1, "Test(s) not yet written: (**) Preorder and inorder sequences of binary trees";
}
else {
    ok 1, '(**) Preorder and inorder sequences of binary trees';
}
