1 files changed, 138 insertions, 0 deletions
diff --git a/python/problems/introduction/ballistics/common.py b/python/problems/introduction/ballistics/common.py
new file mode 100644
index 0000000..1a75493
--- /dev/null
+++ b/python/problems/introduction/ballistics/common.py
@@ -0,0 +1,138 @@
+# coding=utf-8
+
+from python.util import has_token_sequence, string_almost_equal
+from server.hints import Hint, HintSequence
+
+id = 187
+group = 'introduction'
+number = 2
+visible = True
+
+solution = '''\
+from math import *
+g = 9.8
+kot = float(input("Vnesi kot (v stopinjah): "))
+v = float(input("Vnesi hitrost (v m/s): "))
+kot_rad = kot * 2 * pi / 360
+razdalja = v ** 2 * sin(2 * kot_rad) / g
+print("Kroglo bo odneslo", razdalja, "metrov.")
+'''
+
+hint_type = {
+    'plan': Hint('plan'),
+    'eval_expression': Hint('eval_expression'),
+    'sin_error': HintSequence('sin_error', 4),
+    'name_error': HintSequence('name_error', 4),
+    'unsupported_operand': HintSequence('unsupported_operand', 4),
+    'error': HintSequence('error', 2),
+    'radians': HintSequence('radians', 3),
+    'printing': Hint('printing'),
+    'betterg': Hint('betterg'),
+}
+
+import re
+numeric_const_pattern = r"""
+    [-+]? # optional sign
+    (?:
+         (?: \d* \. \d+ ) # .1 .12 .123 etc 9.1 etc 98.1 etc
+         |
+         (?: \d+ \.? ) # 1. 12. 123. etc 1 12 123 etc
+    )
+    # followed by optional exponent part if desired
+    (?: [Ee] [+-]? \d+ ) ?
+    """
+rx = re.compile(numeric_const_pattern, re.VERBOSE)
+
+def contains_negative(s):
+    """ Returns whether the string contains negative value or not.
+    """
+    vals = rx.findall(s)
+    for v in vals:
+        if float(v) < 0:
+            return True
+    return False
+
+def test(python, code):
+    # List of inputs: (expression to eval, stdin).
+    test_in = [
+        (None, '45\n100\n'),
+        (None, '44\n100\n'),
+        (None, '46\n100\n'),
+        (None, '0\n100\n'),
+        (None, '90\n100\n'),
+        (None, '32\n747\n'),
+        (None, '45\n10\n'),
+        (None, '40\n10\n'),
+        (None, '10\n10\n'),
+        (None, '80\n10\n'),
+        (None, '80\n20\n'),
+        (None, '80\n0\n')
+    ]
+
+    test_out = [
+        '1020.4',
+        '1019.79',
+        '1019.79',
+        '0.0',
+        '0.0',
+        '51177.06',
+        '10.20',
+        '10.05',
+        '3.49',
+        '3.49',
+        '13.94',
+        '0'
+    ]
+
+    # List of outputs: (expression result, stdout, stderr, exception).
+    answers = python(code=code, inputs=test_in, timeout=1.0)
+    outputs = [ans[1] for ans in answers]
+
+    n_correct = 0
+    for output, correct in zip(outputs, test_out):
+        if string_almost_equal(output, float(correct)):
+            n_correct += 1
+    return n_correct, len(test_in)
+
+def hint(python, code):
+    # run one test first to see if there are any exceptions
+    test_in = [(None, '5\n10\n')]
+    answer = python(code=code, inputs=test_in, timeout=1.0)
+    exc = answer[0][3]
+    # if have an exception!
+    if exc:
+        if 'sin' in exc and 'NameError' in exc:
+            return [{'id':'sin_error', 'args': {'message': exc}}]
+        elif 'NameError' in exc:
+            return [{'id':'name_error', 'args': {'message': exc}}]
+        elif 'unsupported operand' in exc:
+            return [{'id':'unsupported_operand', 'args': {'message': exc}}]
+        elif 'TypeError' in exc:
+            return [{'id':'type_error', 'args': {'message': exc}}]
+        else:
+            return [{'id':'error', 'args': {'message': exc}}]
+
+    # show plan if student is lost
+    # a) empty progam
+    # b) there is not input (we can do it here, since we have no input hint)
+    if not code or (not has_token_sequence(code, ['input'])):
+        return [{'id': 'plan'}]
+
+    # if sinus is not in code, we need to teach students where they can get it
+    # use math functions.
+    if  (not has_token_sequence(code, ['sin'])):
+        return [{'id' : 'eval_expression'}]
+
+    # student is not using print function
+    if not has_token_sequence(code, ['print']):
+        return [{'id' : 'printing'}]
+
+    # if result is negative, student did not translate to radians
+    if contains_negative(answer[0][1]):
+        return [{'id': 'radians'}]
+
+    # using g=10
+    if string_almost_equal(answer[0][1], 1.736, prec=2):
+        return [{'id': 'betterg'}]
+
+    return None