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
#include <stdbool.h>
#include <stdlib.h>
int findKthLargest(int* nums, int numsSize, int k) {
int positiveArr[10001] = {0};
int negativeArr[10001] = {0};
int cumulativeCount = 0;
int result = 0;
bool found = false;
// Count occurrences of each element
for (int i = 0; i < numsSize; i++) {
if (nums[i] >= 0) {
positiveArr[nums[i]]++;
} else {
negativeArr[abs(nums[i])]++;
}
}
// Search for the k-th largest in positive numbers
for (int i = 10000; i >= 0; i--) {
cumulativeCount += positiveArr[i];
if (cumulativeCount >= k) {
result = i;
found = true;
break;
}
}
// If k-th largest is not found in positive numbers, search in negative numbers
if (!found) {
for (int i = 1; i <= 10000; i++) {
cumulativeCount += negativeArr[i];
if (cumulativeCount >= k) {
result = -i;
break;
}
}
}
return result;
}