Codility solutions - lesson1, exercise: PermMissingElem

Content of Codility excercise:

A zero-indexed 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 a zero-indexed 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.

Assume that:

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)].
Complexity:

expected worst-case time complexity is O(N);
expected worst-case space complexity is O(1), beyond input storage (not counting the storage required for input arguments).
Elements of input arrays can be modified.

Solution:

    public int solution(int[] A) {
        //Create tmp table with only elements equal 0,
        int []tmpB = new int[A.length+1];
        //Store in tmp table all element from table A.
        for (int element: A){
            tmpB[element-1] = element;
        }
        int missingElement = 1;
        int i = 0;
        // Now Tmp table contain one integer equal 0. Our solution will be index increased by 1 of such integer
        while (missingElement != 0){
            missingElement = tmpB[i];
            i++;
        }
        return i;
    }