LeetCode Kth Largest Element in an Array

 1 public class Solution {
 2     public int findKthLargest(int[] nums, int k) {
 3         //QuickSelect
 4         return findK(nums, nums.length-k, 0, nums.length-1);
 5     }
 6     //findK 找第k小，k从0开始
 7     private int findK(int[] nums, int k, int start, int end){
 8         if(start >= end){
 9             return nums[start];
10         }
11         int m = partition(nums, start, end);
12         if(m == k){
13             return nums[m];
14         }else if(m < k){
15             return findK(nums, k, m+1, end);
16         }else{
17             return findK(nums, k, start, m-1);
18         }
19     }
20     
21     private int partition(int[] nums, int start, int end){
22         int pivot = nums[start];
23         int m = start;
24         int n = start + 1;
25         while(n<=end){
26             if(nums[n] < pivot){
27                 swap(nums, ++m, n);
28             }
29             n++;
30         }
31         swap(nums,start,m);
32         return m;
33     }
34     
35     private void swap(int[] nums, int i, int j){
36         int temp = nums[i];
37         nums[i] = nums[j];
38         nums[j] = temp;
39     }
40 }