Tasks Details
easy
Find the missing element in a given permutation.
Task Score
80%
Correctness
100%
Performance
60%
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
Task timeline
Code: 15:04:11 UTC,
java,
autosave
Code: 15:04:19 UTC,
java,
verify,
result: Passed
// 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) {
int[] arr = Arrays
.stream(A)
.sorted()
.toArray();
for(int i=0; i<arr.length; i++){
if(arr[i] != i+1) return i+1;
}
return arr.length+1;
}
}
Analysis
Code: 15:04:24 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) {
int[] arr = Arrays
.stream(A)
.sorted()
.toArray();
for(int i=0; i<arr.length; i++){
if(arr[i] != i+1) return i+1;
}
return arr.length+1;
}
}
Code: 15:04:36 UTC,
java,
verify,
result: Passed
// 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) {
int[] arr = Arrays
.stream(A)
.sorted()
.toArray();
for(int i=0; i<arr.length; i++){
if(arr[i] != i+1) return i+1;
}
return arr.length+1;
}
}
Analysis
Code: 15:04:40 UTC,
java,
final,
score:
80
// 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) {
int[] arr = Arrays
.stream(A)
.sorted()
.toArray();
for(int i=0; i<arr.length; i++){
if(arr[i] != i+1) return i+1;
}
return arr.length+1;
}
}Analysis summary
The following issues have been detected: timeout errors.
Analysis
Detected time complexity:
O(N) or O(N * log(N))
expand all
Correctness tests
1.
0.092 s
OK
2.
0.088 s
OK
1.
0.092 s
OK
2.
0.088 s
OK
1.
0.084 s
OK
2.
0.088 s
OK
1.
0.088 s
OK
2.
0.088 s
OK
3.
0.088 s
OK
1.
0.088 s
OK
expand all
Performance tests
medium1
medium test, length = ~10,000
medium test, length = ~10,000
✘
TIMEOUT ERROR
running time: 0.12 sec., time limit: 0.11 sec.
running time: 0.12 sec., time limit: 0.11 sec.
1.
0.116 s
TIMEOUT ERROR,
running time: 0.12 sec., time limit: 0.11 sec.
medium2
medium test, length = ~10,000
medium test, length = ~10,000
✘
TIMEOUT ERROR
running time: 0.12 sec., time limit: 0.11 sec.
running time: 0.12 sec., time limit: 0.11 sec.
1.
0.116 s
TIMEOUT ERROR,
running time: 0.12 sec., time limit: 0.11 sec.
1.
0.352 s
OK
2.
0.216 s
OK
3.
0.216 s
OK
1.
0.392 s
OK
1.
0.268 s
OK