2、有 8 个字符:c,i,b,u,e,d,a,r, 给定其权值分别为{7,19,2,6,32,3,21,10}, 请 构造哈夫曼树并对字符进行编码。用C语言编写
时间: 2025-01-06 16:50:23 浏览: 63
好的,下面是一个用C语言编写的程序,用于构造哈夫曼树并对字符进行编码。我们将按照以下步骤进行:
1. 定义一个结构体来表示哈夫曼树的节点。
2. 创建一个最小堆来存储节点。
3. 构造哈夫曼树。
4. 对字符进行编码。
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// 定义哈夫曼树的节点结构体
typedef struct HuffmanNode {
char data;
int weight;
struct HuffmanNode *left, *right;
} HuffmanNode;
// 定义最小堆结构体
typedef struct MinHeap {
int size;
int capacity;
HuffmanNode** array;
} MinHeap;
// 创建新的哈夫曼树节点
HuffmanNode* createNode(char data, int weight) {
HuffmanNode* node = (HuffmanNode*)malloc(sizeof(HuffmanNode));
node->data = data;
node->weight = weight;
node->left = node->right = NULL;
return node;
}
// 创建最小堆
MinHeap* createMinHeap(int capacity) {
MinHeap* minHeap = (MinHeap*)malloc(sizeof(MinHeap));
minHeap->size = 0;
minHeap->capacity = capacity;
minHeap->array = (HuffmanNode**)malloc(minHeap->capacity * sizeof(HuffmanNode*));
return minHeap;
}
// 交换两个节点
void swapNodes(HuffmanNode** a, HuffmanNode** b) {
HuffmanNode* t = *a;
*a = *b;
*b = t;
}
// 最小堆化
void minHeapify(MinHeap* minHeap, int idx) {
int smallest = idx;
int left = 2 * idx + 1;
int right = 2 * idx + 2;
if (left < minHeap->size && minHeap->array[left]->weight < minHeap->array[smallest]->weight)
smallest = left;
if (right < minHeap->size && minHeap->array[right]->weight < minHeap->array[smallest]->weight)
smallest = right;
if (smallest != idx) {
swapNodes(&minHeap->array[smallest], &minHeap->array[idx]);
minHeapify(minHeap, smallest);
}
}
// 检查最小堆的大小是否为1
int isSizeOne(MinHeap* minHeap) {
return (minHeap->size == 1);
}
// 提取最小节点
HuffmanNode* extractMin(MinHeap* minHeap) {
HuffmanNode* temp = minHeap->array[0];
minHeap->array[0] = minHeap->array[minHeap->size - 1];
minHeap->size--;
minHeapify(minHeap, 0);
return temp;
}
// 插入节点到最小堆
void insertMinHeap(MinHeap* minHeap, HuffmanNode* node) {
minHeap->size++;
int i = minHeap->size - 1;
while (i && node->weight < minHeap->array[(i - 1) / 2]->weight) {
minHeap->array[i] = minHeap->array[(i - 1) / 2];
i = (i - 1) / 2;
}
minHeap->array[i] = node;
}
// 构建最小堆
void buildMinHeap(MinHeap* minHeap) {
int n = minHeap->size - 1;
for (int i = (n - 1) / 2; i >= 0; --i)
minHeapify(minHeap, i);
}
// 检查一个字符是否在哈夫曼树中
int isInTree(HuffmanNode* root, char data) {
if (root == NULL)
return 0;
if (root->data == data)
return 1;
return isInTree(root->left, data) || isInTree(root->right, data);
}
// 构造哈夫曼树
HuffmanNode* buildHuffmanTree(char data[], int weight[], int size) {
HuffmanNode* left, * right, * top;
MinHeap* minHeap = createMinHeap(size);
for (int i = 0; i < size; ++i)
minHeap->array[i] = createNode(data[i], weight[i]);
minHeap->size = size;
buildMinHeap(minHeap);
while (!isSizeOne(minHeap)) {
left = extractMin(minHeap);
right = extractMin(minHeap);
top = createNode('$', left->weight + right->weight);
top->left = left;
top->right = right;
insertMinHeap(minHeap, top);
}
return extractMin(minHeap);
}
// 打印哈夫曼编码
void printHuffmanCodes(HuffmanNode* root, int arr[], int top) {
if (root->left) {
arr[top] = 0;
printHuffmanCodes(root->left, arr, top + 1);
}
if (root->right) {
arr[top] = 1;
printHuffmanCodes(root->right, arr, top + 1);
}
if (!(root->left) && !(root->right)) {
printf("%c: ", root->data);
for (int i = 0; i < top; ++i)
printf("%d", arr[i]);
printf("\n");
}
}
// 主函数
int main() {
char data[] = {'c', 'i', 'b', 'u', 'e', 'd', 'a', 'r'};
int weight[] = {7, 19, 2, 6, 32, 3, 21, 10};
int size = sizeof(data) / sizeof(data[0]);
HuffmanNode* root = buildHuffmanTree(data, weight, size);
int arr[100], top = 0;
printHuffmanCodes(root, arr, top);
return 0;
}
```
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