配合Dijkstra算法的二叉堆实现文件C语言

最新推荐文章于 2021-07-18 09:30:54 发布

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本文提供了一个二叉堆的数据结构实现案例，包括初始化、插入、删除最小元素等核心操作，并详细展示了上滤与下滤的过程。适用于了解二叉堆的基础实现原理。

/* binary_heap.c -- 二叉堆实现文件 */ #include <stdio.h> #include <stdlib.h> #include "binary_heap.h" /* 局部函数声明 */ static int Percolate_Up (const Binary_Heap * const pbh, const int index) ; static int Percolate_Down (const Binary_Heap * const pbh, const int index) ; /* 接口函数定义 */ int Initialize_B (Binary_Heap * const pbh, const int capacity) { if (capacity < 0) return 0 ; *pbh = (struct binary_heap *) malloc (sizeof (struct binary_heap)) ; if (NULL == *pbh) return 0 ; (*pbh) -> heap = (Heap_Item *) malloc (sizeof (Heap_Item) * (capacity + 1)) ; if (NULL == (*pbh) -> heap) { free (*pbh) ; return 0 ; } (*pbh) -> heap[0] = (Vertex *) malloc (sizeof (Vertex)) ; if (NULL == (*pbh) -> heap[0]) { free ((*pbh) -> heap) ; free (*pbh) ; return 0 ; } (*pbh) -> heap[0] -> dist = NEGATIVEINFINITY ; (*pbh) -> capacity = capacity ; (*pbh) -> current = 0 ; return 1 ; } int Insert_B (const Binary_Heap * const pbh, const Heap_Item hi) { if ((*pbh) -> current == (*pbh) -> capacity) return 0 ; (*pbh) -> heap[++(*pbh) -> current] = hi ; Percolate_Up (pbh, (*pbh) -> current) ; return 1 ; } Heap_Item DeleteMin_B (const Binary_Heap * const pbh) { Heap_Item hi ; if (0 == (*pbh) -> current) return (*pbh) -> heap[0] ; hi = (*pbh) -> heap[1] ; Percolate_Down (pbh, 1) ; (*pbh) -> current-- ; return hi ; } int IncreaseKey_B (const Binary_Heap * const pbh, const int index, const int triangle) { if (0 == (*pbh) -> current || index <= 0 || index > (*pbh) -> current || triangle < 0) return 0 ; (*pbh) -> heap[index] -> dist += triangle ; Percolate_Down (pbh, index) ; return 1 ; } int DecreaseKey_B (const Binary_Heap * const pbh, const int index, const int triangle) { if (0 == (*pbh) -> current || index <= 0 || index > (*pbh) -> current || triangle < 0) return 0 ; (*pbh) -> heap[index] -> dist -= triangle ; Percolate_Up (pbh, index) ; return 1 ; } void Release_B (const Binary_Heap * const pbh) { free ((*pbh) -> heap[0]) ; free ((*pbh) -> heap) ; free (*pbh) ; } /* 局部函数定义 */ static int Percolate_Up (const Binary_Heap * const pbh, const int index) { int dist, i ; if (index <= 0 || index > (*pbh) -> current) return 0 ; dist = (*pbh) -> heap[index] -> dist ; for (i = index; i / 2 > 0; i /= 2) { if (dist < (*pbh) -> heap[i / 2] -> dist) (*pbh) -> heap[i / 2] = (*pbh) -> heap[i] ; else break ; } (*pbh) -> heap[i] = (*pbh) -> heap[index] ; return 1 ; } static int Percolate_Down (const Binary_Heap * const pbh, const int index) { int dist, i, child, current ; if (index <= 0 || index > (*pbh) -> current) return 0 ; current = (*pbh) -> current ; dist = (*pbh) -> heap[current] -> dist ; for (i = index; i * 2 <= current ; i = child) { child = i * 2 ; if (child != current && (*pbh) -> heap[child] -> dist > (*pbh) -> heap[child + 1] -> dist) child++ ; if (dist > (*pbh) -> heap[child] -> dist) (*pbh) -> heap[i] = (*pbh) -> heap[child] ; else break ; } (*pbh) -> heap[i] = (*pbh) -> heap[current] ; return 1 ; }