Question

Given an unsorted array that may contain duplicates. Also given a number k which is smaller than the size of the array. Write a function that returns true if the array contains duplicates within k distance.

Answer 1

To check for duplicates within a k distance in an array, create a set to track unique elements. Loop through the array, compare with the set, keep it updated, and return true if a duplicate is found within the range; otherwise, return false.

Step-by-step explanation:

Checking for Duplicates Within K Distance in an Unsorted Array

To determine if an unsorted array contains duplicates within a specified k distance, a function can be written in various programming languages. In this explanation, we'll discuss a general approach, which can be tailored to a specific language. The function will iterate through the elements of the array using a loop. For each element, the function will check the next k elements to see if a duplicate exists. To optimize, a sliding window concept can be used where a set maintains the unique elements within the current window of size k. As the window slides, the function adds new elements to the set and removes the ones that fall out of the k-distance range.

Here's a step-by-step process:

1. Create a set to store the unique elements within k distance.
2. Loop through each element in the array.
3. For the current element at index i, check if it is present in the set.
4. If the element is found, return true.
5. If the element is not found, add the element to the set.
6. If the set size exceeds k, remove the element from the set that is now out of the k-distance range (the element at index i-k).
7. Continue until all elements are checked or a duplicate is found.
8. If no duplicate is found by the end, return false.

Using this method ensures efficient checking of duplicates within the specified range in the array.