879193. Kth smallest element
Kth smallest element
Summary
Find the kth smallest element in an array. This problem is about manipulating and searching a collection of elements, specifically finding the kth smallest element in a given array. The key concepts involved are data structures and algorithms.
Detailed Explanation
The approach to solve this problem involves using a priority queue or heap data structure. We can use either a min-heap or max-heap depending on whether we want to find the kth largest or kth smallest element, respectively.
Here is a step-by-step breakdown of the solution:
- Initialize an empty priority queue.
- Iterate over the array and push each element into the priority queue.
- Extract the top (smallest) element from the priority queue k-1 times.
- The kth smallest element will be the next element extracted from the priority queue, which is at the top.
Time complexity: O(n log n) where n is the number of elements in the array. This is because each insertion and extraction operation takes O(log n) time, and we perform these operations n times.
Space complexity: O(n) for storing all elements in the priority queue.
Optimized Solutions
Java
import java.util.*;
public class KthSmallest {
public static int findKthSmallest(int[] arr, int k) {
PriorityQueue<Integer> minHeap = new PriorityQueue<>();
for (int num : arr) {
minHeap.offer(num);
}
for (int i = 0; i < k - 1; i++) {
minHeap.poll();
}
return minHeap.peek();
}
}