diff options
Diffstat (limited to 'prolog/problems/sets/count_3')
| -rw-r--r-- | prolog/problems/sets/count_3/common.py | 96 | ||||
| -rw-r--r-- | prolog/problems/sets/count_3/en.py | 11 | ||||
| -rw-r--r-- | prolog/problems/sets/count_3/sl.py | 45 |
3 files changed, 152 insertions, 0 deletions
diff --git a/prolog/problems/sets/count_3/common.py b/prolog/problems/sets/count_3/common.py new file mode 100644 index 0000000..e770eaa --- /dev/null +++ b/prolog/problems/sets/count_3/common.py @@ -0,0 +1,96 @@ +from operator import itemgetter +import socket + +import prolog.engine +import prolog.util +from server.hints import Hint, HintPopup + +id = 120 +number = 10 +visible = True +facts = None + +solution = '''\ +count(_, [], 0). +count(X, [X|T], N) :- + count(X, T, NT), + N is NT + 1. +count(X, [Y|T], NT) :- + X \== Y, + count(X, T, NT). +''' + +hint_type = { + 'eq_instead_of_equ_markup': HintPopup('eq_instead_of_equ_markup'), + 'eq_instead_of_equ': Hint('eq_instead_of_equ'), + 'predicate_always_false': Hint('predicate_always_false'), + 'base_case': Hint('base_case'), + 'recursive_case': Hint('recursive_case'), + 'timeout': Hint('timeout'), +} + +test_cases = [ + ('count(a, [], X)', + [{'X': '0'}]), + ('count(r, [a, r, b, c, r], X)', + [{'X': '2'}]), + ('count(l, [l, l, l, 1, 2, 3], X)', + [{'X': '3'}]), + ('count(z, [a, b, c, z, z], X)', + [{'X': '2'}]), +] + +def test(code, aux_code): + n_correct = 0 + engine_id = None + try: + engine_id, output = prolog.engine.create(code=code+aux_code, timeout=1.0) + 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): + 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 + +def hint(code, aux_code): + tokens = prolog.util.tokenize(code) + + try: + engine_id, output = prolog.engine.create(code=code+aux_code, timeout=1.0) + + # strict equality testing instead of simple matching + # this is usually (but not necessarily) wrong + targets = [prolog.util.Token('EQ', '==')] + marks = [(t.pos, t.pos + len(t.val)) for t in tokens if t in targets] + if marks: + return [{'id': 'eq_instead_of_equ_markup', 'start': m[0], 'end': m[1]} for m in marks] + \ + [{'id': 'eq_instead_of_equ'}] + + # missing/failed base case + if not prolog.engine.ask_truthTO(engine_id, 'count(42, [], 0)'): + return [{'id': 'base_case'}] + + # target predicate seems to always be false + if not prolog.engine.ask_truthTO(engine_id, 'count(_, _, _)'): + return [{'id': 'predicate_always_false'}] + + # base case works, the recursive doesn't (but it doesn't timeout) + # this may be left as the last, most generic hint + if not prolog.engine.ask_truth(engine_id, 'count(42, [2, 41, 42, -22, 42], 2)'): + return [{'id': 'recursive_case'}] + + except socket.timeout as ex: + return [{'id': 'timeout'}] + + finally: + if engine_id: + prolog.engine.destroy(engine_id) + + return [] diff --git a/prolog/problems/sets/count_3/en.py b/prolog/problems/sets/count_3/en.py new file mode 100644 index 0000000..481fd1c --- /dev/null +++ b/prolog/problems/sets/count_3/en.py @@ -0,0 +1,11 @@ +name = 'count/3' +slug = 'find the number of occurrences of an element in list' + +description = '''\ +<p><code>count(X, L, N)</code>: <code>N</code> is the number of times the element <code>X</code> appears in the list <code>L</code>.</p> +<pre> +?- count(1, [1,2,1,3,1], N). + N = 3. +</pre>''' + +hint = {} diff --git a/prolog/problems/sets/count_3/sl.py b/prolog/problems/sets/count_3/sl.py new file mode 100644 index 0000000..1e3f5d2 --- /dev/null +++ b/prolog/problems/sets/count_3/sl.py @@ -0,0 +1,45 @@ +name = 'count/3' +slug = 'Preštej kolikokrat se element pojavi v seznamu' + +description = '''\ +<p><code>count(X, L, N)</code>: <code>N</code> je število kolikokrat se element <code>X</code> pojavi v seznamu <code>L</code>.</p> +<pre> +?- count(1, [1,2,1,3,1], N). + N = 3. +</pre>''' + +hint = { + 'eq_instead_of_equ': '''\ +<p>Operator <code>==</code> je strožji od operatorja <code>=</code> v smislu, da je za slednjega dovolj, +da elementa lahko naredi enaka (unifikacija). Morda z uporabo <code>=</code> narediš predikat +<code>memb/2</code> delujoč tudi v kakšni drugi smeri.</p> +<p>Seveda pa lahko nalogo rešiš brez obeh omenjenih operatorjev, spomni se, da lahko unifikacijo narediš +implicitno že kar v argumentih predikata (glavi stavka).</p> +''', + + 'eq_instead_of_equ_markup': '''\ +<p>Morda bi bil bolj primeren operator za unifikacijo (=)?</p> +''', + + 'base_case': '''\ +<p>Si pomislil na robni pogoj? Kaj je najbolj enostaven primer, ko je element v seznamu? +Do katerega elementa najlažje prideš?</p> +''', + + 'recursive_case': '''\ +<p>Robni primer deluje. Kaj pa rekurzivni, splošni, primer?</p> +''', + + 'predicate_always_false': '''\ +<p>Vse kaže, da tvoj predikat vedno vrne "false". Si mu dal pravilno ime, si se morda pri imenu zatipkal?</p> +<p>Če je ime pravilno, se morda splača preveriti tudi, če se nisi zatipkal kje drugje, +je morda kakšna pika namesto vejice ali obratno, morda kakšna spremenljivka z malo začetnico?</p> +<p>Možno je seveda tudi, da so tvoji pogoji prestrogi ali celo nemogoči (kot bi bila npr. zahteva, +da je <code>X</code> hkrati starš in sestra od <code>Y</code> ali kaj podobno zlobnega).</p> +''', + + 'timeout': '''\ +<p>Je morda na delu potencialno neskončna rekurzija? Kako se bo ustavila?</p> +<p>Morda pa je kriv tudi manjkajoč, neustrezen ali preprosto nekompatibilen (s splošnim primerom) robni pogoj?</p> +''', +} |