1 files changed, 73 insertions, 0 deletions
diff --git a/python/problems/functions/greatest/common.py b/python/problems/functions/greatest/common.py
new file mode 100644
index 0000000..91f773e
--- /dev/null
+++ b/python/problems/functions/greatest/common.py
@@ -0,0 +1,73 @@
+# 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, HintSequence
+
+id = 195
+group = 'functions'
+number = 1
+visible = True
+
+solution = '''\
+def naj(xs):
+    naj = xs[0]
+    for x in xs:
+        if x > naj:
+            naj = x
+    return naj
+'''
+
+hint_type = {
+    'no_def': Hint('no_def'),
+    'no_return': Hint('no_return'),
+    'for_loop': Hint('for_loop'),
+    'if_clause': Hint('if_clause'),
+}
+
+def test(python, code):
+    test_in = [('naj([6, 4, 2, 0])', None),
+               ('naj([4, 6, 2, 0])', None),
+               ('naj([4, 2, 6, 0])', None),
+               ('naj([4, 2, 0, 6])', None),
+               ('naj([6, -8, 2, 0])', None),
+               ('naj([-8, 6, 2, 0])', None),
+               ('naj([-8, -6, -2, 0])', None),
+               ('naj([-8, -6, -2, -1])', None),
+               ('naj([-8, -1, -6, -2])', None),
+               ('naj([-1, -8, -6, -2])', None),
+               ('naj([42])', None),
+               ('naj([-42])', None)]
+
+    test_out = [6, 6, 6, 6, 6, 6, 0, -1, -1, -1, 42, -42]
+
+    answers = python(code=code, inputs=test_in, timeout=1.0)
+    n_correct = sum(ans[0] == to for ans, to in zip(answers, test_out))
+    return n_correct, len(test_in)
+
+def hint(python, code):
+    # run one test first to see if there are any exceptions
+    answer = python(code=code, inputs=[('naj([1, 2, 3, 6, 4, 2, 0])', None)], timeout=1.0)
+    exc = get_exception_desc(answer)
+    if exc: return exc
+
+    tokens = get_tokens(code)
+    # if has no def, tell him to define the function
+    if not has_token_sequence(tokens, ['def']):
+        return [{'id' : 'no_def'}]
+
+    # if has no return, tell him to return the value
+    if not has_token_sequence(tokens, ['return']):
+        return [{'id' : 'no_return'}]
+
+    # if has no loop, tell him to use it
+    if not has_token_sequence(tokens, ['while']) and \
+       not has_token_sequence(tokens, ['for']):
+        return [{'id' : 'for_loop'}]
+
+    # if has no condition if, tell him to use it
+    if not has_token_sequence(tokens, ['if']):
+        return [{'id' : 'if_clause'}]
+
+    return None