K-th element of two sorted Arrays

Problem

Given two sorted arrays arr1 and arr2 of size N and M respectively and an element K. The task is to find the element that would be at the k’th position of the final sorted array.

Solution Approach

Merge 2 array approach.

Expected Time complexity: $O(log(n))$

Click - to see solution code

C++

class Solution {
   public:
    int kthElement(int arr1[], int arr2[], int n, int m, int k) {
        int ele;
        int i = 0, j = 0;
        while (i < n && j < m) {
            if (arr1[i] <= arr2[j]) {
                ele = arr1[i];
                i++;
                if (i + j == k) return ele;
            } else {
                ele = arr2[j];
                j++;
                if (i + j == k) return ele;
            }
        }
        while (i < n) {
            ele = arr1[i++];
            if (i + j == k) return ele;
        }
        while (j < m) {
            ele = arr2[j++];
            if (i + j == k) return ele;
        }
        return -1;
    }
};