Tasks Details
easy
1.
PermCheck
Check whether array A is a permutation.
Task Score
75%
Correctness
83%
Performance
66%
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(int A[], int N);
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 2009–2024 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used C
Time spent on task 8 minutes
Notes
not defined yet
Task timeline
Code: 23:54:07 UTC,
java,
autosave
Code: 23:54:15 UTC,
c,
autosave
// you can write to stdout for debugging purposes, e.g.
// printf("this is a debug message\n");
int solution(int A[], int N) {
// write your code in C99 (gcc 6.2.0)
int i, quo, ren, sum = 0;
sum = 1 + N;
quo = N/2;
if(N%2 == 0)
sum = sum * quo;
else
sum = (sum * quo) + quo + 1;
for(i = 0; i < N; i++)
sum -= A[i];
if(sum == 0)
return 1;
else
return 0;
}
Code: 23:59:15 UTC,
c,
verify,
result: Passed
// you can write to stdout for debugging purposes, e.g.
// printf("this is a debug message\n");
int solution(int A[], int N) {
// write your code in C99 (gcc 6.2.0)
int i, quo, ren, sum = 0;
sum = 1 + N;
quo = N/2;
if(N%2 == 0)
sum = sum * quo;
else
sum = (sum * quo) + quo + 1;
for(i = 0; i < N; i++)
sum -= A[i];
if(sum == 0)
return 1;
else
return 0;
}
Analysis
Code: 23:59:30 UTC,
c,
verify,
result: Passed
// you can write to stdout for debugging purposes, e.g.
// printf("this is a debug message\n");
int solution(int A[], int N) {
// write your code in C99 (gcc 6.2.0)
int i, quo, ren, sum = 0;
sum = 1 + N;
quo = N/2;
if(N%2 == 0)
sum = sum * quo;
else
sum = (sum * quo) + quo + 1;
for(i = 0; i < N; i++)
sum -= A[i];
if(sum == 0)
return 1;
else
return 0;
}
User test case 1:
[1, 2, 3, 4, 5, 6]
Analysis
Code: 00:00:02 UTC,
c,
verify,
result: Passed
// you can write to stdout for debugging purposes, e.g.
// printf("this is a debug message\n");
int solution(int A[], int N) {
// write your code in C99 (gcc 6.2.0)
int i, quo, ren, sum = 0;
sum = 1 + N;
quo = N/2;
if(N%2 == 0)
sum = sum * quo;
else
sum = (sum * quo) + quo + 1;
for(i = 0; i < N; i++)
sum -= A[i];
if(sum == 0)
return 1;
else
return 0;
}
User test case 1:
[1, 2, 3, 4, 5, 6]
User test case 2:
[2, 4, 5, 1, 6, 3]
Analysis
Code: 00:00:20 UTC,
c,
verify,
result: Passed
// you can write to stdout for debugging purposes, e.g.
// printf("this is a debug message\n");
int solution(int A[], int N) {
// write your code in C99 (gcc 6.2.0)
int i, quo, ren, sum = 0;
sum = 1 + N;
quo = N/2;
if(N%2 == 0)
sum = sum * quo;
else
sum = (sum * quo) + quo + 1;
for(i = 0; i < N; i++)
sum -= A[i];
if(sum == 0)
return 1;
else
return 0;
}
User test case 1:
[1, 2, 3, 4, 5, 6]
User test case 2:
[2, 4, 5, 1, 6, 3]
User test case 3:
[1, 2, 6, 7, 8, 9]
Analysis
expand all
User tests
1.
0.001 s
OK
function result: 1
function result: 1
1.
0.001 s
OK
function result: 1
function result: 1
1.
0.001 s
OK
function result: 0
function result: 0
Code: 00:01:32 UTC,
c,
verify,
result: Passed
// you can write to stdout for debugging purposes, e.g.
// printf("this is a debug message\n");
int solution(int A[], int N) {
// write your code in C99 (gcc 6.2.0)
int i, quo, ren, sum = 0;
sum = 1 + N;
quo = N/2;
if(N%2 == 0)
sum = sum * quo;
else
sum = (sum * quo) + quo + 1;
for(i = 0; i < N; i++)
sum -= A[i];
if(sum == 0)
return 1;
else
return 0;
}
User test case 1:
[1, 2, 3, 4, 5, 6]
User test case 2:
[2, 4, 5, 1, 6, 3]
User test case 3:
[1, 2, 6, 7, 8, 9]
Analysis
expand all
User tests
1.
0.001 s
OK
function result: 1
function result: 1
1.
0.001 s
OK
function result: 1
function result: 1
1.
0.001 s
OK
function result: 0
function result: 0
Code: 00:01:35 UTC,
c,
final,
score:
75
// you can write to stdout for debugging purposes, e.g.
// printf("this is a debug message\n");
int solution(int A[], int N) {
// write your code in C99 (gcc 6.2.0)
int i, quo, ren, sum = 0;
sum = 1 + N;
quo = N/2;
if(N%2 == 0)
sum = sum * quo;
else
sum = (sum * quo) + quo + 1;
for(i = 0; i < N; i++)
sum -= A[i];
if(sum == 0)
return 1;
else
return 0;
}Analysis summary
The following issues have been detected: wrong answers.
For example, for the input [1, 4, 1] the solution returned a wrong answer (got 1 expected 0).
Analysis
expand all
Correctness tests
1.
0.001 s
OK
2.
0.001 s
OK
1.
0.001 s
OK
2.
0.001 s
OK
1.
0.001 s
OK
2.
0.001 s
OK
3.
0.001 s
OK
4.
0.001 s
OK
antiSum1
total sum is correct, but it is not a permutation, N <= 10
total sum is correct, but it is not a permutation, N <= 10
✘
WRONG ANSWER
got 1 expected 0
got 1 expected 0
1.
0.001 s
WRONG ANSWER,
got 1 expected 0
2.
0.001 s
WRONG ANSWER,
got 1 expected 0
3.
0.001 s
WRONG ANSWER,
got 1 expected 0
4.
0.001 s
WRONG ANSWER,
got 1 expected 0
1.
0.001 s
OK
2.
0.001 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.
0.001 s
OK
2.
0.001 s
OK
3.
0.001 s
OK
expand all
Performance tests
1.
0.001 s
OK
2.
0.001 s
OK
antiSum2
total sum is correct, but it is not a permutation, N = ~100,000
total sum is correct, but it is not a permutation, N = ~100,000
✘
WRONG ANSWER
got 1 expected 0
got 1 expected 0
1.
0.004 s
WRONG ANSWER,
got 1 expected 0
2.
0.004 s
WRONG ANSWER,
got 1 expected 0
1.
0.004 s
OK
2.
0.004 s
OK
1.
0.004 s
OK
2.
0.004 s
OK
1.
0.001 s
WRONG ANSWER,
got 1 expected 0
2.
0.004 s
OK
3.
0.001 s
OK
1.
0.001 s
OK
2.
0.001 s
OK
3.
0.001 s
OK
4.
0.004 s
OK
5.
0.004 s
OK