[LeetCode] Kth Largest Element in an Array

 1 class Solution {
 2 public:
 3     int findKthLargest(vector<int>& nums, int k) {
 4         int L = 0, R = nums.size() - 1;
 5         while (L < R) {
 6             int left = L, right = R;
 7             int key = nums[left];
 8             while (left < right) {
 9                 while (left < right && nums[right] < key) --right;
10                 nums[left] = nums[right];
11                 while (left < right && nums[left] >= key) ++left;
12                 nums[right] = nums[left];
13             }
14             nums[left] = key;
15             if (left == k - 1) return nums[k - 1];
16             else if (left > k - 1) R = left - 1;
17             else L = left + 1;
18         }
19         return nums[k - 1];
20     }
21 };