Find k-th missing element

Summary

Given an array of distinct integers, find the kth missing integer. This problem involves finding a specific element in an array that is not present, and the key concept is array manipulation.

Detailed Explanation

To solve this problem, we can iterate through the array and maintain a count of the missing elements. We start with a variable missing_count set to 0. Then, for each element i in the array, we check if i+1 (the next integer) is present in the array. If it's not, we increment missing_count. Once we reach k-1, we know that the kth missing element is the one just before the next integer, which would be i+k.

Here's a step-by-step breakdown of the solution:

Initialize missing_count to 0.
Iterate through the array:
- For each element i in the array, check if i+1 (the next integer) is present in the array.
- If it's not, increment missing_count.
Once we reach k-1, return missing_count.

Time complexity: O(n), where n is the size of the input array.

Space complexity: O(1), as we only use a single variable to keep track of the missing count.

Optimized Solutions

Java

public int findKthMissingElement(int[] arr, int k) { int missing_count = 0; for (int i : arr) { if (!contains(arr, i + 1)) { missing_count++; if (missing_count == k - 1) { return i + k; } } } return -1; // or throw an exception } private boolean contains(int[] arr, int target) { for (int i : arr) { if (i == target) { return true; } } return false; }