void minheapify(int i)
{
int min = i;
int lc = 2 * i;
int rc = 2 * i + 1;
if (lc < size && heap[lc].data < heap[min].data)
{
min = lc;
}
if (rc < size && heap[rc].data < heap[min].data)
{
min = rc;
}
if (min != i)
{
heap_2darray temp = heap[i];
heap[i] = heap[min];
heap[min] = temp;
minheapify(min);
}
}
void kth_small(int[,] arr, int k)
{
int ans = -1;
size = arr.GetLength(1);
heap = new heap_2darray[size];
for (int i = 0; i < size; i++)
{
heap[i] = new heap_2darray(0, i, arr[0, i]);
}
for (int i = (size - 1) / 2; i >= 0; i--)
{
minheapify(i);
}
heap_2darray obj = null;
for (int i = 0; i < k; i++)
{
obj = heap[0];
int nextval = obj.i < size - 1 ? arr[obj.i + 1, obj.j] : int.MaxValue;
heap[0] = new heap_2darray(obj.i + 1, obj.j, nextval);
minheapify(0);
}
ans = obj.data;
}