LeetCode-in-All
215. Kth Largest Element in an Array
Medium
Given an integer array nums and an integer k, return the kth largest element in the array.
Note that it is the kth largest element in the sorted order, not the kth distinct element.
You must solve it in O(n) time complexity.
Example 1:
Input: nums = [3,2,1,5,6,4], k = 2
Output: 5
Example 2:
Input: nums = [3,2,3,1,2,4,5,5,6], k = 4
Output: 4
Constraints:
1 <= k <= nums.length <= 105-104 <= nums[i] <= 104
Solution
class Solution {
int findKthLargest(List<int> nums, int k) {
int partition(int low, int high, int pivot) {
for (; low <= high; low++, high--) {
for (; nums[low] < pivot; low++);
for (; nums[high] > pivot; high--);
if (low > high) break;
int temp = nums[low];
nums[low] = nums[high];
nums[high] = temp;
}
return low;
}
void quickSort(int low, int high) {
if (low >= high) {
return;
}
int pivot = nums[(low + high) ~/ 2];
int index = partition(low, high, pivot);
quickSort(low, index - 1);
quickSort(index, high);
}
quickSort(0, nums.length - 1);
return nums[nums.length - k];
}
}