Find Missing And Repeating
Medium Accuracy: 21.24% Submissions: 4474 Points: 4

Given an unsorted array Arr of size N of positive integers. One number 'A' from set {1, 2, …N} is missing and one number 'B' occurs twice in array. Find these two numbers.

Example 1:

N = 2
Arr[] = {2, 2}
Output: 2 1
Explanation: Repeating number is 2 and 
smallest positive missing number is 1.

Example 2:

N = 3
Arr[] = {1, 3, 3}
Output: 3 2
Explanation: Repeating number is 3 and 
smallest positive missing number is 2.

Your Task:
You don't need to read input or print anything. Your task is to complete the function findTwoElement() which takes the array of integers arr and as parameters and returns an array of integers of size 2 denoting the answer ( The first index contains and second index contains A.)

Expected Time Complexity: O(N)
Expected Auxiliary Space: O(1)

1 ≤ N ≤ 105
1 ≤ Arr[i] ≤ N

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