1 files changed, 109 insertions, 0 deletions
diff --git a/python/problems/lists_and_for/counting/common.py b/python/problems/lists_and_for/counting/common.py
new file mode 100644
index 0000000..2d59182
--- /dev/null
+++ b/python/problems/lists_and_for/counting/common.py
@@ -0,0 +1,109 @@
+# coding=utf-8
+
+import re
+from python.util import has_token_sequence, string_almost_equal, \
+    string_contains_number, get_tokens, get_numbers, get_exception_desc
+from server.hints import Hint
+
+id = 203
+group = 'lists_and_for'
+number = 3
+visible = True
+
+solution = '''\
+xs = [42, 5, 4, -7, 2, 12, -3, -4, 11, 42, 2]
+
+stevec = 0
+for x in xs:
+    if x == 42:
+        stevec += 1
+print("Število 42 se v seznamu pojavi", stevec, "krat.")
+'''
+
+hint_type = {
+    'no_xs': Hint('no_xs'),
+    'for_loop': Hint('for_loop'),
+    'if_clause': Hint('if_clause'),
+    'printing': Hint('printing'),
+    'print_out_for': Hint('print_out_for'),
+    'final_hint': Hint('final_hint')
+}
+
+def test(python, code):
+    test_xs = [[42, 5, 4, -7, 2, 42, -3, -4, 11, 42, 2],
+               [42, 5, 4, -7, 2, 12, 42, -4, 11, 2],
+               [5, 4, -7, 2, 12, -3, -4, 11, 2],
+               [],
+               [42],
+               [42, 42],
+               [1, 2, 3, -42],
+               [1, 2, 3, 42, -42]]
+    test_out = [
+        3,
+        2,
+        0,
+        0,
+        1,
+        2,
+        0,
+        1
+    ]
+
+    n_correct = 0
+    tin = None
+    for xs_i, xs in enumerate(test_xs):
+        # change code to contain new xs instead of the one
+        # given by user
+        tcode = re.sub(r'^xs\s*=\s*\[.*?\]',
+                       'xs = ' + str(xs),
+                       code,
+                       flags = re.DOTALL | re.MULTILINE)
+
+        # use python session to call tcode
+        answers = python(code=tcode, inputs=[(None, None)], timeout=1.0)
+        output = answers[0][1]
+
+        if str(test_out[xs_i]) in output:
+            n_correct += 1
+        else:
+            tin = test_xs[xs_i]
+            tout = test_out[xs_i]
+
+    passed = n_correct == len(test_xs)
+    hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_xs)}}]
+    if tin:
+        hints.append({'id': 'problematic_test_case', 'args': {'testin': str(tin), 'testout': str(tout)}})
+    if passed:
+        hints.append({'id': 'final_hint'})
+    return passed, hints
+
+def hint(python, code):
+    # run one test first to see if there are any exceptions
+    answer = python(code=code, inputs=[(None, None)], timeout=1.0)
+    exc = get_exception_desc(answer[0][3])
+    if exc: return exc
+
+    tokens = get_tokens(code)
+
+    # if has no xs, tell him to ask for values
+    if not has_token_sequence(tokens, ['xs', '=', '[']):
+        return [{'id' : 'no_xs'}]
+
+    # student does not have while or for: instruct him on loops
+    if not has_token_sequence(tokens, ['while']) and \
+       not has_token_sequence(tokens, ['for']):
+        return [{'id' : 'for_loop'}]
+
+    if not has_token_sequence(tokens, ['if']):
+        return [{'id' : 'if_clause'}]
+
+    # student is not using print function
+    if not has_token_sequence(tokens, ['print']):
+        return [{'id' : 'printing'}]
+
+    # student is not using print at the beginning of line
+    if not has_token_sequence(tokens, ['\n', 'print']):
+        return [{'id' : 'print_out_for'}]
+
+
+    return None