- new exercises on recursion

- added text (lectures) on conditions and loops

9 files changed, 358 insertions, 0 deletions

diff --git a/python/problems/recursion/binary/common.py b/python/problems/recursion/binary/common.py
new file mode 100644
index 0000000..585c5ff
--- /dev/null
+++ b/python/problems/recursion/binary/common.py
@@ -0,0 +1,75 @@
+import re
+from python.util import has_token_sequence, string_almost_equal, \
+    string_contains_number, get_tokens, get_numbers, get_exception_desc, \
+    all_tokens, has_comprehension, has_loop, almost_equal, get_ast
+from server.hints import Hint
+
+id = 20808
+number = 8
+visible = True
+
+solution = '''\
+def binary(n):
+    if n <= 1:
+        return str(n)
+    return binary(n // 2) + str(n % 2)
+'''
+
+hint_type = {
+    'final_hint': Hint('final_hint'),
+    'has_loop': Hint('has_loop')
+}
+
+def test(python, code, aux_code=''):
+    func_name = 'binary'
+    tokens = get_tokens(code)
+    ast = get_ast(code)
+    if not has_token_sequence(tokens, ['def', func_name]):
+        return False, [{'id' : 'no_func_name', 'args' : {'func_name' : func_name}}]
+
+    in_out = [
+        (3, '11'),
+        (2, '10'),
+        (1, '1'),
+        (0, '0'),
+        (42, '101010')
+    ]
+
+    test_in = [('{0}({1})'.format(func_name, str(l[0])), None)
+               for l in in_out]
+    test_out = [l[1] for l in in_out]
+
+    answers = python(code=aux_code+code, inputs=test_in, timeout=1.0)
+    n_correct = 0
+    tin, tout = None, None
+    for i, (ans, to) in enumerate(zip(answers, test_out)):
+        res = ans[0]
+        corr = res == to
+        n_correct += corr
+        if not corr:
+            tin = test_in[i][0]
+            tout = to
+
+    passed = n_correct == len(test_in)
+    hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_in)}}]
+    if tin:
+        hints.append({'id': 'problematic_test_case', 'args': {'testin': str(tin), 'testout': str(tout)}})
+    if passed:
+        if has_loop(ast):
+            hints.append({'id': 'has_loop'})
+        else:
+            hints.append({'id': 'final_hint'})
+
+
+    return passed, hints
+
+
+def hint(python, code, aux_code=''):
+    tokens = get_tokens(code)
+
+    # run one test first to see if there are any exceptions
+    answer = python(code=aux_code+code, inputs=[(None, None)], timeout=1.0)
+    exc = get_exception_desc(answer[0][3])
+    if exc: return exc
+
+    return None
diff --git a/python/problems/recursion/binary/en.py b/python/problems/recursion/binary/en.py
new file mode 100644
index 0000000..01440f7
--- /dev/null
+++ b/python/problems/recursion/binary/en.py
@@ -0,0 +1,13 @@
+id = 20808
+name = 'Binary'
+
+description = '''\
+<p>(translation missing)</p>'''
+
+hint = {
+    'plan': '''\
+<p>(translation missing)</p>''',
+
+    'no_input_call': '''\
+<p>(translation missing)</p>''',
+}
diff --git a/python/problems/recursion/binary/sl.py b/python/problems/recursion/binary/sl.py
new file mode 100644
index 0000000..8360a46
--- /dev/null
+++ b/python/problems/recursion/binary/sl.py
@@ -0,0 +1,30 @@
+import server
+mod = server.problems.load_language('python', 'sl')
+
+id = 20808
+name = 'Binarno'
+
+description = '''\
+<p>
+Napiši rekurzivno funkcijo <code>binary(n)</code>, ki kot argument prejme število
+<code>n</code> in kot rezultat vrne niz s tem številom v dvojiškem zapisu. </p>
+
+<pre>
+>>> binary(42)
+'101010'
+</pre>
+'''
+
+plan = []
+
+hint = {
+    'final_hint': ['''\
+<p>Program je pravilen! <br>
+</p>
+'''],
+
+    'has_loop': ['''\
+<p>Program sicer deluje pravilno, vendar vsebuje zanko.
+</p>
+'''],
+}
diff --git a/python/problems/recursion/factorial/common.py b/python/problems/recursion/factorial/common.py
new file mode 100644
index 0000000..fec787b
--- /dev/null
+++ b/python/problems/recursion/factorial/common.py
@@ -0,0 +1,75 @@
+import re
+from python.util import has_token_sequence, string_almost_equal, \
+    string_contains_number, get_tokens, get_numbers, get_exception_desc, \
+    all_tokens, has_comprehension, has_loop, almost_equal, get_ast
+from server.hints import Hint
+
+id = 20806
+number = 6
+visible = True
+
+solution = '''\
+def factorial(n):
+    if n == 0:
+        return 1
+    return n * factorial(n - 1)
+'''
+
+hint_type = {
+    'final_hint': Hint('final_hint'),
+    'has_loop': Hint('has_loop')
+}
+
+def test(python, code, aux_code=''):
+    func_name = 'factorial'
+    tokens = get_tokens(code)
+    ast = get_ast(code)
+    if not has_token_sequence(tokens, ['def', func_name]):
+        return False, [{'id' : 'no_func_name', 'args' : {'func_name' : func_name}}]
+
+    in_out = [
+        (0, 1),
+        (1, 1),
+        (2, 2),
+        (12, 479001600),
+        (20, 2432902008176640000)
+    ]
+
+    test_in = [('{0}({1})'.format(func_name, str(l[0])), None)
+               for l in in_out]
+    test_out = [l[1] for l in in_out]
+
+    answers = python(code=aux_code+code, inputs=test_in, timeout=1.0)
+    n_correct = 0
+    tin, tout = None, None
+    for i, (ans, to) in enumerate(zip(answers, test_out)):
+        res = ans[0]
+        corr = res == to
+        n_correct += corr
+        if not corr:
+            tin = test_in[i][0]
+            tout = to
+
+    passed = n_correct == len(test_in)
+    hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_in)}}]
+    if tin:
+        hints.append({'id': 'problematic_test_case', 'args': {'testin': str(tin), 'testout': str(tout)}})
+    if passed:
+        if has_loop(ast):
+            hints.append({'id': 'has_loop'})
+        else:
+            hints.append({'id': 'final_hint'})
+
+
+    return passed, hints
+
+
+def hint(python, code, aux_code=''):
+    tokens = get_tokens(code)
+
+    # run one test first to see if there are any exceptions
+    answer = python(code=aux_code+code, inputs=[(None, None)], timeout=1.0)
+    exc = get_exception_desc(answer[0][3])
+    if exc: return exc
+
+    return None
diff --git a/python/problems/recursion/factorial/en.py b/python/problems/recursion/factorial/en.py
new file mode 100644
index 0000000..616eacd
--- /dev/null
+++ b/python/problems/recursion/factorial/en.py
@@ -0,0 +1,13 @@
+id = 20806
+name = 'Factorial'
+
+description = '''\
+<p>(translation missing)</p>'''
+
+hint = {
+    'plan': '''\
+<p>(translation missing)</p>''',
+
+    'no_input_call': '''\
+<p>(translation missing)</p>''',
+}
diff --git a/python/problems/recursion/factorial/sl.py b/python/problems/recursion/factorial/sl.py
new file mode 100644
index 0000000..a0269e3
--- /dev/null
+++ b/python/problems/recursion/factorial/sl.py
@@ -0,0 +1,37 @@
+import server
+mod = server.problems.load_language('python', 'sl')
+
+id = 20806
+name = 'Fakulteta'
+
+description = '''\
+<p>
+Napiši rekurzivno funkcijo <code>faktorial(n)</code>, ki izračuna n!.
+Funkcija je definirana z enačbama <code>0! = 1</code> in
+<code>n! = n * (n - 1)!</code>.
+Rešitev ne sme vsebovati zanke <code>for</code> ali zanke <code>while</code>.</p>
+<pre>
+>>> faktorial(0)
+1
+>>> faktorial(1)
+1
+>>> faktorial(5)
+120
+>>> faktorial(20)
+2432902008176640000
+</pre>
+'''
+
+plan = []
+
+hint = {
+    'final_hint': ['''\
+<p>Program je pravilen! <br>
+</p>
+'''],
+
+    'has_loop': ['''\
+<p>Program sicer deluje pravilno, vendar vsebuje zanko.
+</p>
+'''],
+}
diff --git a/python/problems/recursion/sum/common.py b/python/problems/recursion/sum/common.py
new file mode 100644
index 0000000..9625a76
--- /dev/null
+++ b/python/problems/recursion/sum/common.py
@@ -0,0 +1,70 @@
+import re
+from python.util import has_token_sequence, string_almost_equal, \
+    string_contains_number, get_tokens, get_numbers, get_exception_desc, \
+    all_tokens, has_comprehension, has_loop, almost_equal, get_ast
+from server.hints import Hint
+
+id = 20807
+number = 7
+visible = True
+
+solution = '''\
+def sum(xs):
+    if not xs:
+        return 0
+    if isinstance(xs[0], list):
+        return sum(xs[0]) + sum(xs[1:])
+    return xs[0] + sum(xs[1:])
+'''
+
+hint_type = {
+    'final_hint': Hint('final_hint')
+}
+
+def test(python, code, aux_code=''):
+    func_name = 'sum'
+    tokens = get_tokens(code)
+    if not has_token_sequence(tokens, ['def', func_name]):
+        return False, [{'id' : 'no_func_name', 'args' : {'func_name' : func_name}}]
+
+    in_out = [
+        ([], 0),
+        ([1,2,3,4,5], 15),
+        ([1, [], [2, 3, [4]], 5], 15),
+        ([1, [], [2, 3, [4]], 5, [[[[10], 6], [[7], 9], 8]]], 55),
+    ]
+
+    test_in = [('{0}({1})'.format(func_name, str(l[0])), None)
+               for l in in_out]
+    test_out = [l[1] for l in in_out]
+
+    answers = python(code=aux_code+code, inputs=test_in, timeout=1.0)
+    n_correct = 0
+    tin, tout = None, None
+    for i, (ans, to) in enumerate(zip(answers, test_out)):
+        res = ans[0]
+        corr = res == to
+        n_correct += corr
+        if not corr:
+            tin = test_in[i][0]
+            tout = to
+
+    passed = n_correct == len(test_in)
+    hints = [{'id': 'test_results', 'args': {'passed': n_correct, 'total': len(test_in)}}]
+    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, aux_code=''):
+    tokens = get_tokens(code)
+
+    # run one test first to see if there are any exceptions
+    answer = python(code=aux_code+code, inputs=[(None, None)], timeout=1.0)
+    exc = get_exception_desc(answer[0][3])
+    if exc: return exc
+
+    return None
diff --git a/python/problems/recursion/sum/en.py b/python/problems/recursion/sum/en.py
new file mode 100644
index 0000000..a61f900
--- /dev/null
+++ b/python/problems/recursion/sum/en.py
@@ -0,0 +1,13 @@
+id = 20807
+name = 'Sum'
+
+description = '''\
+<p>(translation missing)</p>'''
+
+hint = {
+    'plan': '''\
+<p>(translation missing)</p>''',
+
+    'no_input_call': '''\
+<p>(translation missing)</p>''',
+}
diff --git a/python/problems/recursion/sum/sl.py b/python/problems/recursion/sum/sl.py
new file mode 100644
index 0000000..e23bd97
--- /dev/null
+++ b/python/problems/recursion/sum/sl.py
@@ -0,0 +1,32 @@
+import server
+mod = server.problems.load_language('python', 'sl')
+
+id = 20807
+name = 'Vsota seznama'
+
+description = '''\
+<p>
+Napiši funkcijo <code>sum(xs)</code>, ki sešteje elemente vgnezdenega seznama xs.
+Pomagajte si s funkcijo isinstance.</p>
+<pre>
+>>> isinstance([1, 2, 3], list)
+True
+>>> isinstance(1, list)
+False
+>>> sum([])
+0
+>>> sum([1, 2, 3, 4, 5])
+15
+>>> sum([1, [], [2, 3, [4]], 5])
+15
+</pre>
+'''
+
+plan = []
+
+hint = {
+    'final_hint': ['''\
+<p>Program je pravilen! <br>
+</p>
+'''],
+}