[LeetCode]Kth Largest Element in an Array

Kth Largest Element in an Array

经典题目，quicksort 是O(n)，没想明白。。。觉得还是on average在做2分啊

heap 方法是 n*O(k)

import random
class Solution:
    # @param {integer[]} nums
    # @param {integer} k
    # @return {integer}
    def findKthLargest(self, nums, k):
        pivot = random.choice(nums)
        nums1, nums2 = [], []
        for num in nums:
            if num > pivot:
                nums1.append(num)
            elif num < pivot:
                nums2.append(num)
        if k <= len(nums1):
            return self.findKthLargest(nums1, k)
        if k > len(nums) - len(nums2):
            return self.findKthLargest(nums2, k - (len(nums) - len(nums2)))
        return pivot
##另外java heap的做法
public class Solution {
    public int findKthLargest(int[] nums, int k) {
        PriorityQueue
   
   
    
     heap = new PriorityQueue
    
    
     
     ();
        for(int n:nums){
            
            if(heap.size() < k ){
                heap.add(n);
            }else{
                if(n > heap.peek()){
                    heap.poll();
                    heap.add(n);
                }
            }
        }
        return heap.peek();
}
}