Kth Largest Element in an Array

Description

Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element.

Example 1:

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

Example 2:

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

Note:
You may assume k is always valid, 1 ≤ k ≤ array's length.

Solution(javascript)

/**
 * @param {number[]} nums
 * @param {number} k
 * @return {number}
 */
const findKthLargest = function (nums, k) {
  const swap = (a, b) => {
    const temp = nums[a]
    nums[a] = nums[b]
    nums[b] = temp
  }
  const partition = (lo, hi) => {
    let i = lo
    let j = hi + 1
    const v = nums[lo]
    while (true) {
      while (nums[++i] > v) {
        if (i === hi) {
          break
        }
      }
      while (nums[--j] < v) {
        if (j === lo) {
          break
        }
      }
      if (i >= j) {
        break
      }
      swap(i, j)
    }
    swap(lo, j)
    return j
  }
    const select = (lo, hi) => {
        const pivot = partition(lo, hi)
        if(pivot === k-1) {
            return nums[pivot]
        } else if(pivot < k-1) {
            return select(pivot+1, hi)
        } else {
            return select(lo, pivot -1)
        }
    }
    return select(0, nums.length - 1)
}