215. Kth Largest Element in an Array
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.
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 <= 104
- -104 <= nums[i] <= 104
class Solution {
public int findKthLargest(int[] nums, int k) {
int n = nums.length, low = 0, high = n-1;
while(low<=high){
int x = partition(nums, low, high);
if(n-k==x){
return nums[x];
}else if(x<n-k){
low = x+1;
}else{
high = high-1;
}
}
return low;
}
private int partition(int[] nums, int low, int high){
int i = low;
int j = high;
int povit = nums[i];
while(i<j){
while(i<j&&povit<nums[j]){
j--;
}
if(i<j){
nums[i] = nums[j];
nums[j] = povit;
i++;
}
while(i<j&&nums[i]<povit){
i++;
}
if(i<j){
nums[j] = nums[i];
nums[i] = povit;
j--;
}
}
return i;
}
}