easy

Find the missing element in a given permutation.

**Task Score**

**Correctness**

**Performance**

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] = 5`

the 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 2009–2023 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.

Solution

Programming language used Java 8

Total time used 1 minutes

Effective time used 1 minutes

Notes

*not defined yet*

Task timeline