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:
int solution(vector<int> &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 C++
Time spent on task 5 minutes
Notes
not defined yet
Code: 06:59:03 UTC,
java,
autosave
Code: 06:59:14 UTC,
cpp,
autosave
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(A.size()+1, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Code: 07:00:27 UTC,
cpp,
autosave
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(A.size()+1, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Code: 07:00:48 UTC,
cpp,
verify,
result: Passed
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(A.size()+1, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Analysis
expand all
User tests
1.
0.001 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Segmentation Fault
1.
0.001 s
OK
function result: 1
function result: 1
User test case 1:
[1000000001]
User test case 2:
[1]
Code: 07:01:02 UTC,
cpp,
autosave
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(A.size()+1, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Code: 07:01:03 UTC,
cpp,
verify,
result: Passed
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(A.size()+1, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Analysis
expand all
User tests
1.
0.001 s
RUNTIME ERROR,
tested program terminated with exit code 1
stderr:
Segmentation Fault
1.
0.001 s
OK
function result: 1
function result: 1
User test case 1:
[1000000000]
User test case 2:
[1]
Code: 07:02:35 UTC,
cpp,
autosave
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(100, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Code: 07:02:46 UTC,
cpp,
autosave
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(1000000001, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Code: 07:02:54 UTC,
cpp,
verify,
result: Passed
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(1000000001, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Analysis
User test case 1:
[1000000000]
User test case 2:
[1]
Code: 07:03:17 UTC,
cpp,
verify,
result: Passed
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(1000000001, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Analysis
User test case 1:
[1000000000]
User test case 2:
[1]
Code: 07:03:20 UTC,
cpp,
final,
score: 
100
#include <iostream>
using namespace std;
int solution(vector<int> &A) {
// write your code in C++14 (g++ 6.2.0)
vector<bool> number(1000000001, false);
for(int i = 0; i<A.size(); i++){
if(!number[A[i]]) number[A[i]] = true;
else return 0;
}
for(int i =1; i<A.size()+1; i++){
if(!number[i]) return 0;
}
return 1;
}
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N) or O(N * log(N))
expand all
Correctness tests
1.
0.068 s
OK
2.
0.068 s
OK
1.
0.068 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.
0.068 s
OK
4.
0.068 s
OK
1.
0.068 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.
0.072 s
OK
3.
0.068 s
OK
expand all
Performance tests
1.
0.072 s
OK
2.
0.068 s
OK
1.
0.076 s
OK
2.
0.076 s
OK
1.
0.076 s
OK
2.
0.076 s
OK
1.
0.076 s
OK
2.
0.076 s
OK
1.
0.068 s
OK
2.
0.072 s
OK
3.
0.068 s
OK
1.
0.068 s
OK
2.
0.068 s
OK
3.
0.068 s
OK
4.
0.076 s
OK
5.
0.076 s
OK