leetcode--Kth Largest Element in an Array

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.

For example,
Given [3,2,1,5,6,4] and k = 2, return 5.

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

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1. public class Solution {  
2.     public int findKthLargest(int[] nums, int k) {  
3.         if(k>nums.length) return 0;  
4.         int mid = partion(nums, 0, nums.length-1);  
5.         while(mid!=k-1){  
6.             if(mid>k-1){  
7.                 mid = partion(nums, 0, mid-1);  
8.             }else{  
9.                 mid = partion(nums, mid+1, nums.length-1);  
10.             }  
11.         }  
12.         return nums[mid];  
13.     }  
14.           
15.     int partion(int[] nums,int start,int end){  
16.         int t = nums[start];  
17.         while(start<end){  
18.             while(start<end&&nums[end]<=t){  
19.                 end--;  
20.             }  
21.             nums[start] = nums[end];  
22.             while(start<end&&nums[start]>=t){  
23.                 start++;  
24.             }  
25.             nums[end] = nums[start];  
26.         }  
27.         nums[start] = t;  
28.         return start;  
29.     }  
30. }  

原文链接http://blog.youkuaiyun.com/crazy__chen/article/details/46581419