LeetCode-in-All

215. Kth Largest Element in an Array

Medium

Given an integer array nums and an integer k, return the kth largest element in the array.

Note that it is the kth largest element in the sorted order, not the kth distinct element.

You must solve it in O(n) time complexity.

Example 1:

Input: nums = [3,2,1,5,6,4], k = 2

Output: 5

Example 2:

Input: nums = [3,2,3,1,2,4,5,5,6], k = 4

Output: 4

Constraints:

• 1 <= k <= nums.length <= 105
• -104 <= nums[i] <= 104

Solution

(define/contract (find-kth-largest nums k)
  (-> (listof exact-integer?) exact-integer? exact-integer?)
  (let* ([sorted-nums (sort nums >)]  ; Sort in descending order
         [index (- k 1)])             ; Convert 1-based to 0-based index
    (list-ref sorted-nums index)))    ; Return the k-th largest element

This site is open source. Improve this page.