1 // 優先隊列 Heap
 2 // 前綴: Heap
 3 
 4 #ifndef _HEAP_H
 5 #define _HEAP_H     
 6 
 7 #define HEAP_DEFAULT_CAPACITY 10
 8 typedef int Rank;       
 9 typedef int HeapT;
10 typedef struct {
11     int Capacity;   // 容量
12     int Size;       // 元素個數
13     HeapT *Elems;
14 } HeapNode;
15 typedef HeapNode *Heap;
 
16 
17 Heap Heap_Create( int Capa );
18 void Heap_Destroy( Heap *Pheap );
19 void Heap_Insert( Heap H, HeapT E );
20 HeapT Heap_DeleteMin( Heap H );
21 int Heap_IsFull( Heap H );
22 int Heap_IsEmpty( Heap H );
23 
24 // test
25 void Heap_TestPrint(Heap H);
26 
27 #endif /* _HEAP_H */

  1 #include <stdio.h>
  2
 
 #include <stdlib.h>
  3 #include "heap.h"
  4 
  5 Heap Heap_Create(int Capa)
  6 {
  7     if(Capa < HEAP_DEFAULT_CAPACITY) {
  8         Capa = HEAP_DEFAULT_CAPACITY;
  9     }
 10     Heap heap = (Heap)malloc(sizeof(HeapNode));
 11     if(heap == NULL) {
 12         printf("Out of space!!\n
 
");
 13         return NULL;
 14     }
 15     heap->Capacity = Capa + 1;  // 數組0下標處不放數據
 16     heap->Size = 0;
 17     heap->Elems = (HeapT *)malloc(sizeof(HeapT) * (heap->Capacity)); 
 18     if(heap->Elems == NULL) {
 19         free(heap);
 20         printf("Out of space!!\n");
 21         return NULL;
 22     }
 23     return heap;
 24 }
 25 
 26 void Heap_Destroy(Heap *Pheap)
 27 {
 28     if(Pheap != NULL && *Pheap != NULL) {
 29         Heap heap = *Pheap;
 30         free(heap->Elems);
 31         free(heap);
 32         *Pheap = NULL;
 33     }
 34 }
 35 
 36 void Heap_Insert(Heap H, HeapT E)
 37 {
 38     if(H == NULL) return ;
 39     if( Heap_IsFull(H) ) {
 40         printf("Heap is Full!!\n");
 41         return ;
 42     }
 43     
 44     Rank cell = ++(H->Size);
 45     while(cell > 1) {
 46         Rank parent = cell / 2;
 47         if( H->Elems[parent] < E ) {  // 找到插入位置
 48             break;          
 49         } else {  // 未找到位置，上濾
 50             H->Elems[cell] = H->Elems[parent];  
 51             cell = parent;
 52         }
 53     }
 54     // cell位置，要麽是根節點(1)，要麽是插入值小於cell父親的值
 55     H->Elems[cell] = E;
 56 }
 57 
 58 HeapT Heap_DeleteMin(Heap H)
 59 {
 60     if(H == NULL) return ;
 61     if( Heap_IsEmpty(H) ) {
 62         printf("Heap is Empty!!\n");
 63         return ;
 64     }
 65     
 66     HeapT result = H->Elems[1];
 67     HeapT LastElem = H->Elems[H->Size];
 68     H->Size--;
 69     Rank cell = 1;  // LastElem位置
 70     while(2 * cell <= H->Size) { // 當cell左孩子(2 * cell)存在，即cell不是葉子節點
 71         Rank lchild = 2 * cell, rchild = 2 * cell + 1;
 72         Rank minchild = lchild;
 73         if( rchild <= H->Size && H->Elems[rchild] < H->Elems[lchild] ) { // 如果右孩子存在
 74             minchild = rchild;
 75         }
 76         
 77         // 若cell左右孩子中較小的都大於等於LastElem，則cell為LastElem位置
 78         if( H->Elems[minchild] >= LastElem ) {
 79             break;
 80         } else {  // 下濾
 81             H->Elems[cell] = H->Elems[minchild];
 82             cell = minchild;
 83         }
 84     }
 85     // cell的位置，要麽是葉子節點，要麽是cell左右孩子值均小於LastElem
 86     H->Elems[cell] = LastElem;
 87     return result;
 88 }
 89 
 90 int Heap_IsEmpty(Heap H)
 91 {
 92     return H != NULL && H->Size == 0 ? 1 : 0;
 93 }
 94 
 95 int Heap_IsFull(Heap H)
 96 {
 97     return H != NULL && H->Size + 1 == H->Capacity ? 1 : 0;
 98 }
 99 
100 void Heap_TestPrint(Heap H)
101 {
102     if(H == NULL) {
103         printf("Heap is NULL.\n");
104         return ;
105     }
106     for(int i = 1; i < H->Size + 1; i++) {
107         printf("%d ", H->Elems[i]);
108     }
109     printf("\n");
110     printf("Size: %d, Capa: %d\n", H->Size, H->Capacity);
111 }

數據結構之堆