LeetCode 215 Quick Sort space, Insert Sort

leetCode215.js

//Topic: find Kth elements

//quick sort use space
var qsort = function(nums,k) {
  if(nums.length <= 1) {
    return nums
  }
  
    let leftAry = [];
    let rightAry = [];
    let pivot = nums[0];
    for(let i = 1; i < nums.length ; i++){     
      nums[i] > pivot ? rightAry.push(nums[i]) : leftAry.push(nums[i])
    }
  return qsort(leftAry).concat(pivot, qsort(rightAry));
}

//native sort
var nativeSort = (nums,k) => {
  nums.sort((a,b) => a-b)
  return nums[nums.length - k]
}

const swap = (nums,a,b) => {
  [nums[a],nums[b]] = [nums[b],nums[a]]
}

// insert sort
var insertSort = (nums,k) => {
  for(let i = 1; i < nums.length; i++) {
    let position = i;
    while(position >= 0 && nums[position - 1] > nums[position]) {
      swap(nums,position,position-1);
      position--;
    }
   }
  return nums[nums.length - k]
}


var findKthLargest = function(nums, k , sort) {
  return sort(nums,k);
};
const nums = [3,2,1,5,6,4];
const k = 2;
console.log('qsort result:', findKthLargest(nums,k,qsort)[nums.length - k]);
console.log('nativeSort result:', findKthLargest(nums,k,nativeSort))
console.log('insertSort result:', findKthLargest(nums,k,insertSort))