2010北邮上机真题——哈夫曼树

题目描述：

哈夫曼树，第一行输入一个数n，表示叶结点的个数。需要用这些叶结点生成哈夫曼树，根据哈夫曼树的概念，这些结点有权值，即weight，题目需要输出所有结点的值与权值的乘积之和。

输入：

输入有多组数据。
每组第一行输入一个数n，接着输入n个叶节点（叶节点权值不超过100，2<=n<=1000）。

输出：

输出权值。

样例输入：

5  1 2 2 5 9

样例输出：

37

我的困惑

（1）用的数组建立哈夫曼树，然后求出wpl,但是九度上总是报出runtime error的错误，太困惑了，求指导啊，为什嘛啊

（2）用链表实现的哈夫曼树就可以ac，蛋疼啊！

实现代码

顺序表未ac代码

#include <stdio.h>#include <stdlib.h>#define N 2000#define M 2 * N - 1#define MAX 1000struct hfm{int weight;int lchild;int rchild;int parent;};void initHfmtree(struct hfm *);void createHfmtree(struct hfm*, int, int);void calculateLength(struct hfm*, int);int main(){int n, m, i;struct hfm htree[M];while(scanf("%d", &n) != EOF){m = 2 * n - 1;initHfmtree(htree);for(i = 0; i < n; i ++){scanf("%d", &htree[i].weight);}createHfmtree(htree, n, m);calculateLength(htree, n);}return 0;}void initHfmtree(struct hfm *htree){int i;for(i = 0; i < M; i ++){htree[i].weight = 0;htree[i].lchild = htree[i].rchild = htree[i].parent = -1;}}void createHfmtree(struct hfm *htree, int n, int m){int m1, m2, loc1, loc2, i, k;for(i = n; i < m; i ++){m1 = m2 = MAX;loc1 = loc2 = -1;for(k = 0; k < i; k ++){if(htree[k].parent == -1){if(htree[k].weight < m1){m2 = m1;loc2 = loc1;m1 = htree[k].weight;loc1 = k;}else if(htree[k].weight < m2){loc2 = k;m2 = htree[k].weight;}}}htree[loc1].parent = i;htree[loc2].parent = i;htree[i].weight = m1 + m2;htree[i].lchild = loc1;htree[i].rchild = loc2;}}void calculateLength(struct hfm *htree, int n){int p, i, count, sum;sum = 0;for(i = 0; i < n; i ++){count = 0;p = htree[i].parent;while(p != -1){count ++;p = htree[p].parent;}sum += count * htree[i].weight;}printf("%d\n", sum);}

链表ac代码

#include <stdio.h>#include <stdlib.h>#include <string.h>//哈夫曼结点类型定义struct huffmancode{int power;struct huffmancode *lchild;struct huffmancode *rchild;struct huffmancode *next;};//栈类型定义struct stack{struct huffmancode* data[100];int top;};//函数声明void addNode(struct huffmancode*, struct huffmancode *);struct huffmancode* createHuffmanTree(int, int *);void preTraverse(struct huffmancode*);int getWPL(struct huffmancode*, int);void freeHuffmantree(struct huffmancode *);int main(){int n, i, wpl;int weight[1001];struct huffmancode *root;while(scanf("%d", &n) != EOF){//接收权值数据for(i = 0; i < n; i ++){scanf("%d", weight + i);}//构建哈夫曼树root = createHuffmanTree(n, weight);//获取wplwpl = getWPL(root, 0);printf("%d\n", wpl);//清理哈夫曼树freeHuffmantree(root);}return 0;}/** * Description:构建哈夫曼树 */struct huffmancode* createHuffmanTree(int n, int *weight){int i;struct huffmancode *head, *pl, *pr, *proot;head = (struct huffmancode *)malloc(sizeof(struct huffmancode));head->next = NULL;//初始化森林for(i = 0; i < n; i ++){struct huffmancode *pnode = (struct huffmancode *)malloc(sizeof(struct huffmancode));pnode->power = *(weight + i);pnode->lchild = pnode->rchild = pnode->next = NULL;addNode(head, pnode);}//构造哈夫曼树while(head->next->next){//只有一个节点的情况if(!head->next->next){break;}//从单链表中取出节点最小的两个点pl = head->next;pr = pl->next;//删除pl、pr结点，加入到哈夫曼树中head->next = pr->next;proot = (struct huffmancode *)malloc(sizeof(struct huffmancode));proot->power = pl->power + pr->power;proot->lchild = pl;proot->rchild = pr;addNode(head, proot);}return head->next;}/** * Description:添加节点 */void addNode(struct huffmancode *head, struct huffmancode *pnode){struct huffmancode *t = head;//找到第一个权值大于给定结点的结点，t指定该结点的前一结点while(t->next && t->next->power < pnode->power){t = t->next;}pnode->next = t->next;t->next = pnode;}/** * Description:前序遍历 */void preTraverse(struct huffmancode *root){struct huffmancode *head = root;struct stack *s = (struct stack *)malloc(sizeof(struct stack));s->top = 0;while(head || s->top > 0){if(head){printf("%d ", head->power);s->data[s->top ++] = head;head = head->lchild;}else{head = s->data[-- s->top];head = head->rchild;}}}/** * Description:获取哈夫曼树的带权路径长度 */int getWPL(struct huffmancode *root, int level){if(!root){return 0;}if(!root->lchild && !root->rchild){return root->power * level;}return getWPL(root->lchild, level + 1) + getWPL(root->rchild, level + 1);}/** * Description:清理哈夫曼树 */void freeHuffmantree(struct huffmancode *root){if(!root){return;}freeHuffmantree(root->lchild);freeHuffmantree(root->rchild);free(root);}

后记

各位，留言指导我一下吧，真心是求指导啊，不知道哪里就数组越界了！！