heap相关算法的简单实现

// 12:06 PM/09/28/2017
#pragma once
//向下调整算法 主要用来make_heap 以及pop_heap
inline void adjustDown(int* heap, const int first, const int last)
{
    if (last == first + 1)return;
    int value = heap[first];
    int hole = first;//当前要调整的节点
    int childHole = hole * 2;//其左子女节点
    while (childHole < last)//当左子女节点存
    {
        if (childHole < last - 1 && heap[childHole] < heap[childHole + 1])//如果左右子女都存在
            childHole++;
        if (value > heap[childHole]) break;

        {
            //当待调整元素 比子女元素小是，将子女元素移动到父节点
            heap[hole] = heap[childHole];
            hole = childHole;//将该子女元素设置为洞
            childHole = hole * 2;
        }
    }
    heap[hole] = value;
}

//像上调整 实际上也就是 pop_heap
inline void adjustUp(int* heap, const int first, const int last)
{
    if (last == first + 1)return;
    int hole = last - 1;//最后一个元素设置为洞
    int parentHole = hole / 2;//该元素的父节点
    int value = heap[last - 1];//当前要调整元素
    while (parentHole >= first && value > heap[parentHole])//父节点存在，且当前值大于父节点
    {
        heap[hole] = heap[parentHole];//父节点的值给当前洞
        hole = parentHole;//父节点设置为洞
        parentHole = hole / 2;
    }
    heap[hole] = value;
}

inline void push_heap(int* heap, const int firstIndex, const int lastIndex)
{
    adjustUp(heap, firstIndex, lastIndex);
}

//弹出最大元素
inline void pop_head(int* heap, const int firstIndex, const int lastIndex)
{
    int value = heap[firstIndex];//要弹出的元素
    heap[firstIndex] = heap[lastIndex - 1];//把最后一个元素给要弹出的
    heap[lastIndex - 1] = value;//要弹出的放到最后
    adjustDown(heap, firstIndex, lastIndex - 1);//进行向下调整
}

inline void sort_heap(int* heap, int firstIndex, int lastIndex)
{
    int curLast = lastIndex;
    while (curLast > firstIndex)
    {
        pop_head(heap, firstIndex, curLast);
        curLast--;
    }
}

inline void make_heap(int* heap, int firstIndex, int lastIndex)
{
    int hole = (lastIndex - 1) / 2;
    while (hole >= firstIndex)
    {
        adjustDown(heap, hole, lastIndex);
        hole--;
    }
}

inline void partial_sort(int* heap, const int first, const int middle, const int last)
{
    int i = middle;
    make_heap(heap, first, middle);
    while (i < last)
    {
        if (heap[i] < heap[first])
        {
            int value = heap[first];
            heap[first] = heap[i];
            heap[i] = value;
            adjustDown(heap, first, middle);
        }
        i++;
    }
    sort_heap(heap, first, middle);
}