Tasks Details
easy
1.
BinaryGap
Find longest sequence of zeros in binary representation of an integer.
Task Score
100%
Correctness
100%
Performance
Not assessed
A binary gap within a positive integer N is any maximal sequence of consecutive zeros that is surrounded by ones at both ends in the binary representation of N.
For example, number 9 has binary representation 1001 and contains a binary gap of length 2. The number 529 has binary representation 1000010001 and contains two binary gaps: one of length 4 and one of length 3. The number 20 has binary representation 10100 and contains one binary gap of length 1. The number 15 has binary representation 1111 and has no binary gaps. The number 32 has binary representation 100000 and has no binary gaps.
Write a function:
def solution(N)
that, given a positive integer N, returns the length of its longest binary gap. The function should return 0 if N doesn't contain a binary gap.
For example, given N = 1041 the function should return 5, because N has binary representation 10000010001 and so its longest binary gap is of length 5. Given N = 32 the function should return 0, because N has binary representation '100000' and thus no binary gaps.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [1..2,147,483,647].
Copyright 2009–2025 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Python
Time spent on task 11 minutes
Notes
not defined yet
Code: 14:36:40 UTC,
java,
autosave
Code: 14:37:50 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
example1
example test n=1041=10000010001_2
example test n=1041=10000010001_2
✘
RUNTIME ERROR
tested program terminated with exit code 1
tested program terminated with exit code 1
1.
0.052 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
1041
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
15
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
32
Code: 14:38:31 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
example1
example test n=1041=10000010001_2
example test n=1041=10000010001_2
✘
RUNTIME ERROR
tested program terminated with exit code 1
tested program terminated with exit code 1
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
0b10000010001
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
0b1111
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
0b100000
Code: 14:40:31 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
example1
example test n=1041=10000010001_2
example test n=1041=10000010001_2
✘
RUNTIME ERROR
tested program terminated with exit code 1
tested program terminated with exit code 1
1.
0.044 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
<class 'str'>
1.
0.044 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
<class 'str'>
1.
0.044 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
<class 'str'>
Code: 14:40:52 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
example1
example test n=1041=10000010001_2
example test n=1041=10000010001_2
✘
RUNTIME ERROR
tested program terminated with exit code 1
tested program terminated with exit code 1
1.
0.052 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
1 0 0 0 0 0 1 0 0 0 1
1.
0.052 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
1 1 1 1
1.
0.048 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
1 0 0 0 0 0
Code: 14:42:10 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
example1
example test n=1041=10000010001_2
example test n=1041=10000010001_2
✘
RUNTIME ERROR
tested program terminated with exit code 1
tested program terminated with exit code 1
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 64, in main
sol = __import__('solution')
File "/tmp/solution.py", line 9
else: print("reset)
^
SyntaxError: EOL while scanning string literal
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 64, in main
sol = __import__('solution')
File "/tmp/solution.py", line 9
else: print("reset)
^
SyntaxError: EOL while scanning string literal
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 64, in main
sol = __import__('solution')
File "/tmp/solution.py", line 9
else: print("reset)
^
SyntaxError: EOL while scanning string literal
Code: 14:42:16 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
example1
example test n=1041=10000010001_2
example test n=1041=10000010001_2
✘
RUNTIME ERROR
tested program terminated with exit code 1
tested program terminated with exit code 1
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
reset reset reset reset reset reset reset reset reset reset reset
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
reset reset reset reset
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
reset reset reset reset reset reset
Code: 14:42:24 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
example1
example test n=1041=10000010001_2
example test n=1041=10000010001_2
✘
RUNTIME ERROR
tested program terminated with exit code 1
tested program terminated with exit code 1
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
reset inc inc inc inc inc reset inc inc inc reset
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
reset reset reset reset
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.stdout:
reset inc inc inc inc inc
Code: 14:44:01 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
example1
example test n=1041=10000010001_2
example test n=1041=10000010001_2
✘
RUNTIME ERROR
tested program terminated with exit code 1
tested program terminated with exit code 1
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.
1.
0.036 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Invalid result type, int expected, <class 'NoneType'> found.
Code: 14:44:14 UTC,
py,
verify,
result: Failed
Analysis
Code: 14:44:42 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
1.
0.036 s
OK
stdout:
10000010001
1.
0.036 s
OK
stdout:
1111
1.
0.036 s
WRONG ANSWER,
got 5 expected 0
stdout:
100000
Code: 14:45:11 UTC,
py,
verify,
result: Passed
Analysis
expand all
Example tests
1.
0.036 s
OK
stdout:
10000010001
1.
0.036 s
OK
stdout:
1111
1.
0.036 s
OK
stdout:
100000
Code: 14:45:31 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
example1
example test n=1041=10000010001_2
example test n=1041=10000010001_2
✘
RUNTIME ERROR
tested program terminated with exit code 1
tested program terminated with exit code 1
1.
0.052 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 64, in main
sol = __import__('solution')
File "/tmp/solution.py", line 11
else if i == '1':
^
SyntaxError: invalid syntax
1.
0.052 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 64, in main
sol = __import__('solution')
File "/tmp/solution.py", line 11
else if i == '1':
^
SyntaxError: invalid syntax
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 64, in main
sol = __import__('solution')
File "/tmp/solution.py", line 11
else if i == '1':
^
SyntaxError: invalid syntax
Code: 14:45:35 UTC,
py,
autosave
Code: 14:45:37 UTC,
py,
verify,
result: Passed
Analysis
expand all
Example tests
1.
0.036 s
OK
stdout:
10000010001
1.
0.052 s
OK
stdout:
1111
1.
0.052 s
OK
stdout:
100000
Code: 14:46:10 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(N):
maxx =0
cnt =0
print(bin(N)[2:])
for i in bin(N)[2:]:
if i == '0':
cnt = cnt +1
elif i == '1':
if cnt > maxx: maxx=cnt
cnt = 0
return maxx
User test case 1:
[2]
Analysis
expand all
Example tests
1.
0.036 s
OK
stdout:
10000010001
1.
0.036 s
OK
stdout:
1111
1.
0.036 s
OK
stdout:
100000
Code: 14:46:17 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(N):
maxx =0
cnt =0
print(bin(N)[2:])
for i in bin(N)[2:]:
if i == '0':
cnt = cnt +1
elif i == '1':
if cnt > maxx: maxx=cnt
cnt = 0
return maxx
User test case 1:
[3]
Analysis
expand all
Example tests
1.
0.036 s
OK
stdout:
10000010001
1.
0.036 s
OK
stdout:
1111
1.
0.036 s
OK
stdout:
100000
Code: 14:46:38 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(N):
maxx =0
cnt =0
for i in bin(N)[2:]:
if i == '0':
cnt = cnt +1
elif i == '1':
if cnt > maxx: maxx=cnt
cnt = 0
return maxx
User test case 1:
[3]
Analysis
Code: 14:46:41 UTC,
py,
final,
score:
100
Analysis summary
The solution obtained perfect score.
Analysis
expand all
Correctness tests
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
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
1.
0.036 s
OK
2.
0.036 s
OK
1.
0.036 s
OK
2.
0.036 s
OK
1.
0.036 s
OK
2.
0.036 s
OK
1.
0.036 s
OK
2.
0.036 s
OK
1.
0.032 s
OK
1.
0.036 s
OK
1.
0.036 s
OK
1.
0.036 s
OK
1.
0.036 s
OK
1.
0.036 s
OK
1.
0.036 s
OK