2 files changed, 37 insertions, 0 deletions
diff --git a/prolog/problems/trees/maxt_2/common.py b/prolog/problems/trees/maxt_2/common.py
new file mode 100644
index 0000000..be51d46
--- /dev/null
+++ b/prolog/problems/trees/maxt_2/common.py
@@ -0,0 +1,25 @@
+id = 143
+group = 'trees'
+number = 50
+visible = True
+facts = None
+
+solution = '''\
+max143([X], X).
+max143([H|T], Max):-
+  max143(T, Max1),
+  ( H > Max1, Max is H
+    ;
+    H =< Max1, Max is Max1 ).
+
+maxT(t(E), E) :- !.
+maxT(Tree, Max) :-
+  Tree =.. [t, E|SubTrees],
+  getMaxElems(SubTrees, MaxElems),
+  max143([E|MaxElems], Max).
+
+getMaxElems([], []).
+getMaxElems([SubTree|SubTrees], [MaxElem|MaxElems]) :-
+  maxT(SubTree, MaxElem),
+  getMaxElems(SubTrees, MaxElems).
+'''
diff --git a/prolog/problems/trees/maxt_2/en.py b/prolog/problems/trees/maxt_2/en.py
new file mode 100644
index 0000000..3e15b34
--- /dev/null
+++ b/prolog/problems/trees/maxt_2/en.py
@@ -0,0 +1,12 @@
+id = 143
+name = 'maxT/2'
+slug = 'find the greatest element in a tree'
+
+description = '''\
+<p><code>maxT(Tree, Max)</code>: <code>Max</code> is the greatest element in the tree <code>Tree</code>.</p>
+<pre>
+  ?- maxT(t(1, t(2), t(3)), Max).
+    Max = 3.
+</pre>'''
+
+hint = {}