hacktoberfest/create kth element at 2ff4530d57c7bbe4e6f15dc24062226c758a56de · keshavsingh3197/hacktoberfest · GitHub

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typedef struct
{
    int *heap;    // Min-heap to store k largest elements
    int size;     // Current number of elements in heap
    int capacity; // Maximum size (k)
} KthLargest;
int kthLargestAdd(KthLargest* kth, int val);
KthLargest* kthLargestCreate(int k, int* nums, int numsSize)
{
    KthLargest *kth = (KthLargest*)malloc(sizeof(KthLargest));
    kth->heap = (int*)malloc(sizeof(int) * k);
    kth->size = 0;
    kth->capacity = k;
    for (int i = 0; i < numsSize; i++)
    {
        kthLargestAdd(kth, nums[i]);
    }
    return kth;
}
int kthLargestAdd(KthLargest* kth, int val)
{
    if (kth->size < kth->capacity)
    {
        int i = kth->size;
        kth->heap[kth->size++] = val;
        while (i > 0)
        {
            int parent = (i - 1) / 2;
            if (kth->heap[i] < kth->heap[parent])
            {
                int temp = kth->heap[i];
                kth->heap[i] = kth->heap[parent];
                kth->heap[parent] = temp;
                i = parent;
            }
            else {
                break;
            }
        }
    }
    else if (val > kth->heap[0])
    {
        kth->heap[0] = val;
        int i = 0;
        while (1)
        {
            int left = 2 * i + 1;
            int right = 2 * i + 2;
            int smallest = i;

            if (left < kth->size && kth->heap[left] < kth->heap[smallest])
            {
                smallest = left;
            }
            if (right < kth->size && kth->heap[right] < kth->heap[smallest])
            {
                smallest = right;
            }
            if (smallest != i)
            {
                int temp = kth->heap[i];
                kth->heap[i] = kth->heap[smallest];
                kth->heap[smallest] = temp;
                i = smallest;
            }
            else {
                break;
            }
        }
    }
    return kth->heap[0];
}
void kthLargestFree(KthLargest* kth)
{
    free(kth->heap);
    free(kth);
}