3 files changed, 77 insertions, 0 deletions
diff --git a/prolog/problems/world_data/similar_population_3/common.py b/prolog/problems/world_data/similar_population_3/common.py
new file mode 100644
index 0000000..11d541b
--- /dev/null
+++ b/prolog/problems/world_data/similar_population_3/common.py
@@ -0,0 +1,47 @@
+from operator import itemgetter
+import socket
+import prolog.engine
+from server.hints import Hint
+import server.problems
+
+id = 12519
+number = 1
+visible = True
+facts = 'mondial'
+
+solution = '''\
+simpop(X, Y, D):-
+  findall(D/X/Y, (country(X,_,_,_,_,PX), country(Y,_,_,_,_,PY), X \== Y, D is abs(PX-PY)), L),
+  sort(L, [D/X/Y|_]).
+'''
+
+test_cases = [
+    ('simpop(X, Y, D)',
+        [{'X': "'Grenada'", 'Y': "'Tonga'", 'D': '76'}]),
+    ("simpop('Slovenia', Y, D)",
+        [{'Y': "'Macedonia'", 'D': '973'}]),
+    ("simpop(X, 'Australia', D)",
+        [{'X': "'Taiwan'", 'D': '180541'}]),
+    ("simpop(X, Y, 1176831)",
+        [{'X': "'Uzbekistan'", 'Y': "'Venezuela'"}]),
+]
+
+def test(code, aux_code):
+    n_correct = 0
+    engine_id = None
+    try:
+        engine_id, output = prolog.engine.create(code=code+aux_code, timeout=5.0)
+        if engine_id is not None and 'error' not in map(itemgetter(0), output):
+            # Engine successfully created, and no syntax error in program.
+            for query, answers in test_cases:
+                if prolog.engine.check_answers(engine_id, query=query, answers=answers, timeout=1.0, inference_limit = None):
+                    n_correct += 1
+    except socket.timeout:
+        pass
+    finally:
+        if engine_id:
+            prolog.engine.destroy(engine_id)
+
+    hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_cases)}}]
+    return n_correct, len(test_cases), hints
+
diff --git a/prolog/problems/world_data/similar_population_3/en.py b/prolog/problems/world_data/similar_population_3/en.py
new file mode 100644
index 0000000..e9c2516
--- /dev/null
+++ b/prolog/problems/world_data/similar_population_3/en.py
@@ -0,0 +1,15 @@
+name = 'simpop/3'
+slug = 'countries with most similar number of residents'
+
+description = '''\
+<p><code>simpop(X, Y, Diff)</code>: <code>X</code> and <code>Y</code> are countries with the most similar numbers of
+residents. <code>Diff</code> represents the difference between them.</p>
+<pre>
+?- simpop('Fiji', Y, Diff).
+  Y = 'Cyprus',
+  Diff = 20152.
+</pre>
+<p>Useful facts are given as <code>country(Name, ID, Capital, CapitalProvince, Size, Population).</code></p>
+'''
+
+hint = {}
diff --git a/prolog/problems/world_data/similar_population_3/sl.py b/prolog/problems/world_data/similar_population_3/sl.py
new file mode 100644
index 0000000..069f35e
--- /dev/null
+++ b/prolog/problems/world_data/similar_population_3/sl.py
@@ -0,0 +1,15 @@
+name = 'simpop/3'
+slug = 'državi z najbolj podobnim številom prebivalcev'
+
+description = '''\
+<p><code>simpop(X, Y, Diff)</code>: <code>X</code> in <code>Y</code> je par držav z najbolj podobnim številom
+prebivalcev, <code>Diff</code> je razlika med njima.</p>
+<pre>
+?- simpop('Fiji', Y, Diff).
+  Y = 'Cyprus',
+  Diff = 20152.
+</pre>
+<p>Uporabna dejstva so podana v obliki <code>country(Name, ID, Capital, CapitalProvince, Size, Population).</code></p>
+'''
+
+hint = {}