坠小二叉堆的一些方法

来源：互联网发布：abs资产证券化知乎编辑：程序博客网时间：2024/06/11 19:40

•堆其实是一颗完全二叉树

•任何一非叶子节点的关键字不大于或者不小于其左右子节点的关键字

•如左图所示，为最小堆

•堆的存储结构为顺序结构，以左图为例，其在顺序表中的存储序列为{15,18,30,45,35,36,48,93,53,72}

Father= (Child-1)/2

LeftChild=Father*2+1

RightChild=Father*2+2

package BinaryHeap;public class BinaryHeap {public int value;public int capacity=15;        public int length=0;public int[] heap=new int[capacity];public int currentcapacity;public void insert(int x){heap[length]=x;            currentcapacity=length+1;    int currentindex=length;    int father=(currentindex-1)/2;    while(father>=0 && heap[father]>heap[currentindex])    {       int exchange=heap[father];       heap[father]=heap[currentindex];       heap[currentindex]=exchange;       exchange=father;       father=(father-1)/2;       currentindex=exchange;    }    length++;}public void BinaryHeap(int x){   insert(x);}public void Delete(int x){   int i=0;   //找到这个数在堆中的位置   while(heap[i]!=x)   i++;   heap[i]=heap[length-1];         heap[length-1]=0;    while(heap[i]>Math.max(heap[i*2+1], heap[i*2+2])&& i*2+2<length-1)    {    int change=heap[i];    if(heap[i*2+1]>heap[i*2+2])     {    heap[i]=heap[i*2+2];    heap[i*2+2]=change;    i=i*2+2;    }        else {    heap[i]=heap[i*2+1];    heap[i*2+1]=change;    i=i*2+1;    }        }    length--;}public void IncreaseKey(int delta,int x){ int i=0;   //找到这个数在堆中的位置   while(heap[i]!=x)   i++;    heap[i]=heap[i]+delta;    while(heap[i]>Math.max(heap[i*2+1], heap[i*2+2])&& i*2+2<length-1)    {    int change=heap[i];    if(heap[i*2+1]>heap[i*2+2])     {    heap[i]=heap[i*2+2];    heap[i*2+2]=change;    i=i*2+2;    }        else {    heap[i]=heap[i*2+1];    heap[i*2+1]=change;    i=i*2+1;    }        }   }public void DecreaseKey(int delta,int x){int i=0;   //找到这个数在堆中的位置   while(heap[i]!=x)   i++;    heap[i]=heap[i]-delta;    while(heap[i]<heap[(i-1)/2]&&(i-1)/2>=0)    {    int change=heap[i];    heap[i]=heap[(i-1)/2];    heap[(i-1)/2]=change;    i=(i-1)/2;    }}       public void PrintHeap()       {       System.out.println("打印出来当前堆");       for(int i=0;i<length;i++)       {       System.out.print(heap[i]+" ");       }       System.out.println();       }}

package BinaryHeap;public class MainMethod {public static void main(String[] args){int[] input={32,12,14,55,23,16,30,49};BinaryHeap h=new BinaryHeap();for(int i=0;i<input.length;i++){h.insert(input[i]);}h.IncreaseKey(17, 16);h.PrintHeap();h.DecreaseKey(6, 14);h.PrintHeap();h.Delete(12);h.PrintHeap();}}

运行结果：

打印出来当前堆
12 23 14 49 32 33 30 55
打印出来当前堆
8 23 12 49 32 33 30 55
打印出来当前堆
8 23 30 49 32 33 55

0 0