Tasks Details
easy
1.
Nesting
Determine whether a given string of parentheses (single type) is properly nested.
Task Score
100%
Correctness
100%
Performance
100%
A string S consisting of N characters is called properly nested if:
- S is empty;
- S has the form "(U)" where U is a properly nested string;
- S has the form "VW" where V and W are properly nested strings.
For example, string "(()(())())" is properly nested but string "())" isn't.
Write a function:
def solution(S)
that, given a string S consisting of N characters, returns 1 if string S is properly nested and 0 otherwise.
For example, given S = "(()(())())", the function should return 1 and given S = "())", the function should return 0, as explained above.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [0..1,000,000];
- string S is made only of the characters '(' and/or ')'.
Copyright 2009–2024 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Python
Time spent on task 10 minutes
Notes
not defined yet
Task timeline
Code: 16:50:22 UTC,
java,
autosave
Code: 16:54:10 UTC,
py,
autosave
Code: 16:54:28 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Traceback (most recent call last): File "exec.py", line 123, in <module> main() File "exec.py", line 85, in main result = solution( S ) File "/tmp/solution.py", line 12, in solution elif s == nest[s]: KeyError: ')'
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Traceback (most recent call last): File "exec.py", line 123, in <module> main() File "exec.py", line 85, in main result = solution( S ) File "/tmp/solution.py", line 12, in solution elif s == nest[s]: KeyError: ')'
Code: 16:55:48 UTC,
py,
autosave
Code: 16:55:50 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
1.
0.040 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Traceback (most recent call last): File "exec.py", line 123, in <module> main() File "exec.py", line 85, in main result = solution( S ) File "/tmp/solution.py", line 12, in solution elif s == nest[s]: KeyError: ')'
1.
0.044 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Traceback (most recent call last): File "exec.py", line 123, in <module> main() File "exec.py", line 85, in main result = solution( S ) File "/tmp/solution.py", line 12, in solution elif s == nest[s]: KeyError: ')'
Code: 16:56:50 UTC,
py,
autosave
Code: 16:56:59 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
1.
0.036 s
OK
stdout:
) ) ) ) )
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Traceback (most recent call last): File "exec.py", line 123, in <module> main() File "exec.py", line 85, in main result = solution( S ) File "/tmp/solution.py", line 14, in solution stack.pop() IndexError: pop from empty liststdout:
) )
Code: 16:57:03 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
1.
0.036 s
OK
1.
0.040 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Traceback (most recent call last): File "exec.py", line 123, in <module> main() File "exec.py", line 85, in main result = solution( S ) File "/tmp/solution.py", line 13, in solution stack.pop() IndexError: pop from empty list
Code: 16:57:21 UTC,
py,
autosave
Code: 16:57:44 UTC,
py,
autosave
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
if not stack:
return 1
else:
return 0
Code: 16:57:53 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
Analysis
Code: 16:58:08 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
User test case 1:
['']
User test case 2:
['vv']
User test case 3:
[')(']
Analysis
expand all
User tests
1.
0.036 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 0
function result: 0
Code: 16:58:42 UTC,
py,
autosave
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
Code: 16:58:47 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
User test case 1:
['']
User test case 2:
['vv']
User test case 3:
[')(']
User test case 4:
[')']
User test case 5:
['(']
Analysis
Code: 16:59:02 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
User test case 1:
['']
User test case 2:
['vv']
User test case 3:
[')(']
User test case 4:
[')']
User test case 5:
['(']
User test case 6:
['()()(()))']
Analysis
expand all
User tests
1.
0.036 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
Code: 16:59:12 UTC,
py,
autosave
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
Code: 16:59:19 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
User test case 1:
['']
User test case 2:
['vv']
User test case 3:
[')(']
User test case 4:
[')']
User test case 5:
['(']
User test case 6:
['()()(()))']
User test case 7:
['vv()vvvs(vv)']
Analysis
expand all
User tests
1.
0.036 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 1
function result: 1
Code: 16:59:27 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
User test case 1:
['']
User test case 2:
['vv']
User test case 3:
[')(']
User test case 4:
[')']
User test case 5:
['(']
User test case 6:
['()()(()))']
User test case 7:
['vv()vvvs(vv))']
Analysis
expand all
User tests
1.
0.040 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
Code: 16:59:35 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
User test case 1:
['']
User test case 2:
['vv']
User test case 3:
[')(']
User test case 4:
[')']
User test case 5:
['(']
User test case 6:
['()()(()))']
User test case 7:
['vv()vvvs(vv))']
Analysis
expand all
User tests
1.
0.036 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 1
function result: 1
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
1.
0.036 s
OK
function result: 0
function result: 0
Code: 16:59:38 UTC,
py,
final,
score: 
100
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(S):
nest = {"(":")"}
stack = []
for s in S:
if s in nest.keys():
stack.append(s)
elif s in nest.values():
if stack:
stack.pop()
else:
return 0
if not stack:
return 1
else:
return 0
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N)
expand all
Correctness tests
1.
0.036 s
OK
2.
0.036 s
OK
1.
0.036 s
OK
1.
0.036 s
OK
2.
0.036 s
OK
3.
0.036 s
OK
1.
0.036 s
OK
2.
0.036 s
OK
3.
0.036 s
OK
expand all
Performance tests
1.
0.044 s
OK
2.
0.044 s
OK
3.
0.036 s
OK
1.
0.096 s
OK
2.
0.036 s
OK
multiple_full_binary_trees
sequence of full trees of the form T=(TT), depths [1..10..1], with/without unmatched ')' at the end, length=49K+
sequence of full trees of the form T=(TT), depths [1..10..1], with/without unmatched ')' at the end, length=49K+
✔
OK
1.
0.052 s
OK
2.
0.052 s
OK
3.
0.036 s
OK
broad_tree_with_deep_paths
string of the form (TTT...T) of 300 T's, each T being '(((...)))' nested 200-fold, length=1 million
string of the form (TTT...T) of 300 T's, each T being '(((...)))' nested 200-fold, length=1 million
✔
OK
1.
0.344 s
OK
2.
0.036 s
OK