ICODEBROKER

■ 힙 정렬하기 예제

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using System;

int[] array = new int[] { 10, 50, 30, 20, 90, 80, 15, 20 };

HeapSort<int>(array);

for(int i = 0; i < array.Length; i++)

{

    Console.Write(array[i]);

    Console.Write(" ");

}

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■ 힙 정렬하기

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using System;

#region 힙 정렬하기 - HeapSort<TItem>(itemArray, count)

/// <summary>

/// 힙 정렬하기

/// </summary>

/// <typeparam name="T">항목 타입</typeparam>

/// <param name="itemArray">항목 배열</param>

/// <param name="count">횟수</param>

public void HeapSort<T>(T[] itemArray, int count) where T : IComparable

{

    HeapDown(itemArray, count);

    int endIndex = count - 1;

    while(endIndex > 0)

    {

        T temporaryItem = itemArray[endIndex];

        itemArray[endIndex] = itemArray[0];

        itemArray[0       ] = temporaryItem;

        SiftDown(itemArray, 0, endIndex - 1);

        endIndex--;

    }

}

#endregion

#region 힙 정렬하기 - HeapSort<T>(itemArray)

/// <summary>

/// 힙 정렬하기

/// </summary>

/// <typeparam name="T">항목 타입</typeparam>

/// <param name="itemArray">항목 배열</param>

public void HeapSort<T>(T[] itemArray) where T : IComparable

{

    HeapSort(itemArray, itemArray.Length);

}

#endregion

#region 아래로 이동하기 - SiftDown<T>(itemArray, startIndex, endIndex)

/// <summary>

/// 아래로 이동하기

/// </summary>

/// <typeparam name="T">항목 타입</typeparam>

/// <param name="itemArray">항목 배열</param>

/// <param name="startIndex">시작 인덱스</param>

/// <param name="endIndex">종료 인덱스</param>

private void SiftDown<T>(T[] itemArray, int startIndex, int endIndex) where T : IComparable

{

    int rootIndex = startIndex;

    while(rootIndex * 2 + 1 <= endIndex)

    {

        int childIndex = rootIndex * 2 + 1;

        if(childIndex < endIndex && itemArray[childIndex].CompareTo(itemArray[childIndex + 1]) < 0)

        {

            childIndex++;

        }

        if(itemArray[rootIndex].CompareTo(itemArray[childIndex]) < 0)

        {

            T temporaryItem = itemArray[rootIndex];

            itemArray[rootIndex ] = itemArray[childIndex];

            itemArray[childIndex] = temporaryItem;

            rootIndex = childIndex;

        }

        else

        {

            return;

        }

    }

}

#endregion

#region 아래로 쌓기 - HeapDown<T>(itemArray, count)

/// <summary>

/// 아래로 쌓기

/// </summary>

/// <typeparam name="T">항목 타입</typeparam>

/// <param name="itemArray">항목 배열</param>

/// <param name="count">횟수</param>

private void HeapDown<T>(T[] itemArray, int count) where T : IComparable

{

    int startIndex = (count - 2) / 2;

    while(startIndex >= 0)

    {

        SiftDown(itemArray, startIndex, count - 1);

        startIndex--;

    }

}

#endregion

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