Tasks Details
easy
1.
PermCheck
Check whether array A is a permutation.
Task Score
100%
Correctness
100%
Performance
100%
A non-empty array A consisting of N integers is given.
A permutation is a sequence containing each element from 1 to N once, and only once.
For example, array A such that:
A[0] = 4 A[1] = 1 A[2] = 3 A[3] = 2is a permutation, but array A such that:
A[0] = 4 A[1] = 1 A[2] = 3is not a permutation, because value 2 is missing.
The goal is to check whether array A is a permutation.
Write a function:
def solution(A)
that, given an array A, returns 1 if array A is a permutation and 0 if it is not.
For example, given array A such that:
A[0] = 4 A[1] = 1 A[2] = 3 A[3] = 2the function should return 1.
Given array A such that:
A[0] = 4 A[1] = 1 A[2] = 3the function should return 0.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [1..100,000];
- each element of array A is an integer within the range [1..1,000,000,000].
Copyright 2009–2025 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Python
Time spent on task 8 minutes
Notes
not defined yet
Code: 13:23:26 UTC,
java,
autosave
Code: 13:26:29 UTC,
py,
verify,
result: Failed
Analysis
Code: 13:26:52 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
1.
0.036 s
WRONG ANSWER,
got 0 expected 1
stdout:
[1, 2, 3, 4]
1.
0.036 s
OK
stdout:
[1, 3, 4]
Code: 13:27:43 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
1.
0.036 s
WRONG ANSWER,
got 0 expected 1
stdout:
[1, 2, 3, 4]
1.
0.036 s
OK
stdout:
[1, 3, 4]
Code: 13:27:57 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
1.
0.036 s
WRONG ANSWER,
got 0 expected 1
stdout:
[1, 2, 3, 4]
1.
0.036 s
OK
stdout:
[1, 3, 4]
Code: 13:28:25 UTC,
py,
verify,
result: Failed
Analysis
expand all
Example tests
1.
0.036 s
WRONG ANSWER,
got 0 expected 1
stdout:
[1, 2, 3, 4] 1 3
1.
0.036 s
OK
stdout:
[1, 3, 4] 1 4
Code: 13:28:47 UTC,
py,
verify,
result: Passed
Analysis
expand all
Example tests
1.
0.036 s
OK
stdout:
[1, 2, 3, 4] 1 1 2 2 3 3
1.
0.036 s
OK
stdout:
[1, 3, 4] 1 2
Code: 13:29:16 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(A):
A.sort()
x = 0;
print(A)
for i in range(0,len(A)-1):
if A[i] != A[i+1]-1:
return 0
return 1
User test case 1:
[1]
Analysis
Code: 13:29:42 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(A):
A.sort()
x = 0;
print(A)
for i in range(0,len(A)-1):
if A[i] != A[i+1]-1:
return 0
return 1
User test case 1:
[2]
Analysis
Code: 13:30:12 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(A):
A.sort()
x = 0;
if A[0] != 1: return 0
for i in range(0,len(A)-1):
if A[i] != A[i+1]-1:
return 0
return 1
User test case 1:
[2]
Analysis
Code: 13:30:25 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(A):
A.sort()
x = 0;
if A[0] != 1: return 0
for i in range(0,len(A)-1):
if A[i] != A[i+1]-1:
return 0
return 1
User test case 1:
[2]
Analysis
Code: 13:30:28 UTC,
py,
verify,
result: Passed
# you can write to stdout for debugging purposes, e.g.
# print("this is a debug message")
def solution(A):
A.sort()
x = 0;
if A[0] != 1: return 0
for i in range(0,len(A)-1):
if A[i] != A[i+1]-1:
return 0
return 1
User test case 1:
[2]
Analysis
Code: 13:30:30 UTC,
py,
final,
score: 
100
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N) or O(N * log(N))
expand all
Correctness tests
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
3.
0.036 s
OK
4.
0.036 s
OK
1.
0.036 s
OK
2.
0.036 s
OK
3.
0.036 s
OK
4.
0.036 s
OK
1.
0.036 s
OK
2.
0.036 s
OK
permutations_of_ranges
permutations of sets like [2..100] for which the anwsers should be false
permutations of sets like [2..100] for which the anwsers should be false
✔
OK
1.
0.036 s
OK
2.
0.036 s
OK
3.
0.036 s
OK
expand all
Performance tests
1.
0.048 s
OK
2.
0.048 s
OK
1.
0.136 s
OK
2.
0.136 s
OK
1.
0.168 s
OK
2.
0.176 s
OK
1.
0.152 s
OK
2.
0.152 s
OK
1.
0.036 s
OK
2.
0.128 s
OK
3.
0.036 s
OK
1.
0.036 s
OK
2.
0.036 s
OK
3.
0.048 s
OK
4.
0.148 s
OK
5.
0.184 s
OK