// use max priority queue of size k
// since insert/delete are O(lg k), time complexity O(N lg k)
public static int KthSmallest(int[] a, int k)
{
MaxPQ pq = new MaxPQ(k);
for (int i = 0; i < a.Length; i++)
{
if (i < k)
pq.Insert(a[i]);
else
if (pq.GetMax() > a[i])
{
pq.DeleteMax();
pq.Insert(a[i]);
}
}
return pq.GetMax();
}
// use max priority queue of size k
// since insert/delete are O(lg k), time complexity O(N lg k)
public static int KthSmallest(int[] a, int k)
{
MaxPQ pq = new MaxPQ(k);
for (int i = 0; i < a.Length; i++)
{
if (i < k)
{
pq.Insert(a[i]);
}
else
if (pq.GetMax() > a[i])
{
pq.DeleteMax();
pq.Insert(a[i]);
}
}
return(pq.GetMax());
}
public static void Test()
{
int[] array = { 3, 1, 2, 5, 6, 7, 9, 10, 4, 8 };
MaxPQ pq = new MaxPQ(array);
for (int i = 0; i < array.Length; i++)
{
Console.Write(pq.DeleteMax() + " "); // 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
}
Console.WriteLine();
pq = new MaxPQ(2);
for (int i = 0; i < array.Length; i++)
{
pq.Insert(array[i]);
}
while (pq.Count() > 0)
{
Console.Write(pq.DeleteMax() + " "); // 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
}
Console.WriteLine();
}
public static void Test()
{
int[] array = { 3, 1, 2, 5, 6, 7, 9, 10, 4, 8 };
MaxPQ pq = new MaxPQ(array);
for (int i = 0; i < array.Length; i++)
Console.Write(pq.DeleteMax() + " "); // 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
Console.WriteLine();
pq = new MaxPQ(2);
for (int i = 0; i < array.Length; i++)
pq.Insert(array[i]);
while (pq.Count() > 0)
Console.Write(pq.DeleteMax() + " "); // 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
Console.WriteLine();
}