Tasks Details
easy
Find the missing element in a given permutation.
Task Score
50%
Correctness
20%
Performance
80%
An array A consisting of N different integers is given. The array contains integers in the range [1..(N + 1)], which means that exactly one element is missing.
Your goal is to find that missing element.
Write a function:
class Solution { public int solution(int[] A); }
that, given an array A, returns the value of the missing element.
For example, given array A such that:
A[0] = 2 A[1] = 3 A[2] = 1 A[3] = 5the function should return 4, as it is the missing element.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [0..100,000];
- the elements of A are all distinct;
- each element of array A is an integer within the range [1..(N + 1)].
Copyright 2009–2025 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Java 8
Time spent on task 1 minutes
Notes
not defined yet
Code: 09:41:27 UTC,
java,
autosave
Code: 09:41:35 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
Arrays.sort(A);
for (int i=0; i<A.length; i++) {
if (i+1 != A[i]) {
return i+1;
}
}
return 1;
}
}
Code: 09:41:44 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
import java.util.Arrays;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
Arrays.sort(A);
for (int i=0; i<A.length; i++) {
if (i+1 != A[i]) {
return i+1;
}
}
return 1;
}
}
User test case 1:
[]
Analysis
Code: 09:41:58 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
import java.util.Arrays;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
Arrays.sort(A);
for (int i=0; i<A.length; i++) {
if (i+1 != A[i]) {
return i+1;
}
}
return 1;
}
}
User test case 1:
[]
Analysis
Code: 09:42:02 UTC,
java,
final,
score:
50
// you can also use imports, for example:
// import java.util.*;
import java.util.Arrays;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// write your code in Java SE 8
Arrays.sort(A);
for (int i=0; i<A.length; i++) {
if (i+1 != A[i]) {
return i+1;
}
}
return 1;
}
}
Analysis summary
The following issues have been detected: wrong answers.
For example, for the input [1] the solution returned a wrong answer (got 1 expected 2).
Analysis
expand all
Correctness tests
1.
0.004 s
OK
2.
0.004 s
WRONG ANSWER,
got 1 expected 2
1.
0.008 s
WRONG ANSWER,
got 1 expected 6
2.
0.004 s
OK
1.
0.004 s
WRONG ANSWER,
got 1 expected 2
2.
0.008 s
OK
1.
0.004 s
WRONG ANSWER,
got 1 expected 3
2.
0.004 s
OK
3.
0.004 s
OK
1.
0.004 s
OK
expand all
Performance tests
1.
0.028 s
OK
1.
0.032 s
OK
1.
0.244 s
WRONG ANSWER,
got 1 expected 100001
2.
0.124 s
OK
3.
0.124 s
OK
1.
0.288 s
OK
1.
0.176 s
OK