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:
function 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 JavaScript
Time spent on task 10 minutes
Notes
not defined yet
Code: 01:01:14 UTC,
java,
autosave
Code: 01:02:59 UTC,
js,
verify,
result: Passed
// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');
function solution(A) {
let max = 0
for (let i = 0; i < A.length; i++){
if (A[i] > max) max = A[i]
}
if (A.length !== max) return 0
let Indexes = Array(max).fill(0)
for (let i = 0; i < A.length; i++){
Indexes[A[i]-1]++
}
result = Indexes.indexOf(0)
if (result === -1) {
return 1
} else {
return 0
} // write your code in JavaScript (Node.js 8.9.4)
}
Analysis
Code: 01:10:18 UTC,
js,
verify,
result: Passed
// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');
function solution(A) {
let max = 0
for (let i = 0; i < A.length; i++){
if (A[i] > max) max = A[i]
}
if (A.length !== max) return 0
let Indexes = Array(max).fill(0)
for (let i = 0; i < A.length; i++){
Indexes[A[i]-1]++
}
result = Indexes.indexOf(0)
if (result === -1) {
return 1
} else {
return 0
} // write your code in JavaScript (Node.js 8.9.4)
}
Analysis
Code: 01:10:21 UTC,
js,
final,
score:
100
// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');
function solution(A) {
let max = 0
for (let i = 0; i < A.length; i++){
if (A[i] > max) max = A[i]
}
if (A.length !== max) return 0
let Indexes = Array(max).fill(0)
for (let i = 0; i < A.length; i++){
Indexes[A[i]-1]++
}
result = Indexes.indexOf(0)
if (result === -1) {
return 1
} else {
return 0
} // write your code in JavaScript (Node.js 8.9.4)
}
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N) or O(N * log(N))
expand all
Correctness tests
1.
0.072 s
OK
2.
0.072 s
OK
1.
0.072 s
OK
2.
0.068 s
OK
1.
0.068 s
OK
2.
0.068 s
OK
3.
0.068 s
OK
4.
0.068 s
OK
1.
0.068 s
OK
2.
0.068 s
OK
3.
0.072 s
OK
4.
0.068 s
OK
1.
0.072 s
OK
2.
0.068 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.
0.068 s
OK
2.
0.068 s
OK
3.
0.072 s
OK
expand all
Performance tests
1.
0.080 s
OK
2.
0.080 s
OK
1.
0.112 s
OK
2.
0.116 s
OK
1.
0.108 s
OK
2.
0.108 s
OK
1.
0.112 s
OK
2.
0.108 s
OK
1.
0.068 s
OK
2.
0.096 s
OK
3.
0.072 s
OK
1.
0.072 s
OK
2.
0.072 s
OK
3.
0.080 s
OK
4.
0.116 s
OK
5.
0.116 s
OK