int getWPL(HuffmanTree tree, int n) { int wpl = 0; for (int i = 0; i < n; i++) { int j = i; while (tree[j].parent != -1) { if (j == tree[tree[j].parent].left_child) { wpl += tree[j].weight * (i + 1); } j = tree[j].parent; } } return wpl; }
时间: 2023-12-30 12:06:51 浏览: 15
这是一个求Huffman编码的带权路径长度WPL的函数。其中,HuffmanTree是一个数组表示Huffman树的结构体,n是Huffman树中节点的数量。函数中的主要思路是遍历Huffman树中的所有叶子节点,对于每个叶子节点,计算它到根节点的路径长度(即该节点的深度),并将该节点的权值乘以它到根节点的路径长度,在累加到WPL中。最后返回WPL即可。
需要注意的是,这里的i表示当前节点的编号,而不是它的深度。在while循环中,不断将当前节点向上移动到它的父节点,直到移动到根节点为止。对于每个节点,如果它是它父节点的左孩子,则将它的权值乘以当前节点的深度,并累加到WPL中。最终得到的WPL即为Huffman树的带权路径长度。
相关问题
C语言完成以下代码:给出n个结点的描述,构造一棵哈夫曼树。输入第一行是一个正整数t。 接下来有t组数据,每组数据有两行。 第一行是一个正整数n,表示有n个结点。 第二行是n个整数,第i个整数mi表示编号为i的结点权重为mi。 (0<t<100, 1<=n<=1000, 0<mi<=100)每组数据输出一个整数,表示哈夫曼树的带权路径长度。
以下是C语言实现:
```c
#include <stdio.h>
#include <stdlib.h>
#define MAX_N 1000
typedef struct huffman_node {
int weight;
int parent;
int left_child;
int right_child;
} HuffmanNode;
void build_huffman_tree(HuffmanNode *nodes, int n);
int get_min_weight_node(HuffmanNode *nodes, int n, int *index1, int *index2);
int main() {
int t;
scanf("%d", &t);
while (t--) {
int n, i;
scanf("%d", &n);
HuffmanNode nodes[MAX_N];
for (i = 0; i < n; i++) {
scanf("%d", &nodes[i].weight);
nodes[i].parent = -1;
nodes[i].left_child = -1;
nodes[i].right_child = -1;
}
build_huffman_tree(nodes, n);
int wpl = 0;
for (i = 0; i < n; i++) {
int depth = 0;
int j = i;
while (nodes[j].parent != -1) {
depth++;
j = nodes[j].parent;
}
wpl += nodes[i].weight * depth;
}
printf("%d\n", wpl);
}
return 0;
}
void build_huffman_tree(HuffmanNode *nodes, int n) {
int i, index1, index2;
for (i = n; i < 2 * n - 1; i++) {
get_min_weight_node(nodes, i, &index1, &index2);
nodes[i].weight = nodes[index1].weight + nodes[index2].weight;
nodes[index1].parent = i;
nodes[index2].parent = i;
nodes[i].left_child = index1;
nodes[i].right_child = index2;
}
}
int get_min_weight_node(HuffmanNode *nodes, int n, int *index1, int *index2) {
int i, min1, min2;
*index1 = -1;
*index2 = -1;
min1 = min2 = 0x7fffffff;
for (i = 0; i < n; i++) {
if (nodes[i].parent == -1) {
if (nodes[i].weight < min1) {
min2 = min1;
min1 = nodes[i].weight;
*index2 = *index1;
*index1 = i;
} else if (nodes[i].weight < min2) {
min2 = nodes[i].weight;
*index2 = i;
}
}
}
return min1 + min2;
}
```
该代码采用了一个结构体 `HuffmanNode` 来表示哈夫曼树的节点,其中包括权重、父节点、左右子节点等信息。`build_huffman_tree` 函数实现了构建哈夫曼树的算法,采用了贪心策略,即每次选择权重最小的两个节点合并,直到只剩下一个节点。`get_min_weight_node` 函数用于寻找当前未被合并的节点中权重最小的两个。
最后计算哈夫曼树的带权路径长度(WPL),即将每个节点的权重乘以其深度,再将所有节点的结果相加即可。
用c语言写一个算法计算哈夫曼树的WPL值
哈夫曼树的WPL(加权路径长度)是指所有叶子节点的权值乘以它们到根节点的路径长度之和,可以通过以下步骤来计算哈夫曼树的WPL值:
1. 定义哈夫曼树的结构体
```c
typedef struct Node {
int weight; // 权值
int parent; // 父节点编号
int left_child; // 左子节点编号
int right_child; // 右子节点编号
} Node, *HuffmanTree;
```
2. 定义比较函数
```c
int cmp(const void *a, const void *b) {
return ((Node *)a)->weight - ((Node *)b)->weight;
}
```
3. 构造哈夫曼树
```c
void createHuffmanTree(HuffmanTree tree, int n) {
int i, m1, m2, x1, x2;
for (i = 0; i < 2 * n - 1; i++) {
tree[i].weight = 0;
tree[i].parent = -1;
tree[i].left_child = -1;
tree[i].right_child = -1;
}
for (i = 0; i < n; i++) {
scanf("%d", &tree[i].weight);
}
qsort(tree, n, sizeof(Node), cmp);
for (i = n; i < 2 * n - 1; i++) {
m1 = m2 = INT_MAX;
x1 = x2 = -1;
for (int j = 0; j < i; j++) {
if (tree[j].parent == -1) {
if (tree[j].weight < m1) {
m2 = m1;
x2 = x1;
m1 = tree[j].weight;
x1 = j;
} else if (tree[j].weight < m2) {
m2 = tree[j].weight;
x2 = j;
}
}
}
tree[x1].parent = i;
tree[x2].parent = i;
tree[i].left_child = x1;
tree[i].right_child = x2;
tree[i].weight = m1 + m2;
}
}
```
4. 计算WPL值
```c
int getWPL(HuffmanTree tree, int n) {
int wpl = 0;
for (int i = 0; i < n; i++) {
int j = i;
while (tree[j].parent != -1) {
if (j == tree[tree[j].parent].left_child) {
wpl += tree[j].weight * (i + 1);
}
j = tree[j].parent;
}
}
return wpl;
}
```
完整代码如下:
```c
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
typedef struct Node {
int weight; // 权值
int parent; // 父节点编号
int left_child; // 左子节点编号
int right_child; // 右子节点编号
} Node, *HuffmanTree;
int cmp(const void *a, const void *b) {
return ((Node *)a)->weight - ((Node *)b)->weight;
}
void createHuffmanTree(HuffmanTree tree, int n) {
int i, m1, m2, x1, x2;
for (i = 0; i < 2 * n - 1; i++) {
tree[i].weight = 0;
tree[i].parent = -1;
tree[i].left_child = -1;
tree[i].right_child = -1;
}
for (i = 0; i < n; i++) {
scanf("%d", &tree[i].weight);
}
qsort(tree, n, sizeof(Node), cmp);
for (i = n; i < 2 * n - 1; i++) {
m1 = m2 = INT_MAX;
x1 = x2 = -1;
for (int j = 0; j < i; j++) {
if (tree[j].parent == -1) {
if (tree[j].weight < m1) {
m2 = m1;
x2 = x1;
m1 = tree[j].weight;
x1 = j;
} else if (tree[j].weight < m2) {
m2 = tree[j].weight;
x2 = j;
}
}
}
tree[x1].parent = i;
tree[x2].parent = i;
tree[i].left_child = x1;
tree[i].right_child = x2;
tree[i].weight = m1 + m2;
}
}
int getWPL(HuffmanTree tree, int n) {
int wpl = 0;
for (int i = 0; i < n; i++) {
int j = i;
while (tree[j].parent != -1) {
if (j == tree[tree[j].parent].left_child) {
wpl += tree[j].weight * (i + 1);
}
j = tree[j].parent;
}
}
return wpl;
}
int main() {
int n;
printf("请输入叶子节点的个数:");
scanf("%d", &n);
HuffmanTree tree = (HuffmanTree)malloc(sizeof(Node) * (2 * n - 1));
createHuffmanTree(tree, n);
int wpl = getWPL(tree, n);
printf("哈夫曼树的WPL值为:%d\n", wpl);
free(tree);
return 0;
}
```
相关推荐
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)