北邮机试——huffman权值问题

我的Online Judge账号还没有这道题的访问权限（1172），这让我情何以堪，好在还是找到了题目，题目想做的比较好还是需要一些功底的。

做一下，马上就复试了，注释也没时间写，代码能看清楚：

  1 /*

  2  * author: xuangong

  3  * time: 2013-4-9 21:42

  4  */

  5 #include <stdio.h>

  6 #include <stdlib.h>

  7 

  8 typedef struct _huffmannode

  9 {

 10     int data;

 11     struct _huffmannode *lchild;

 12     struct _huffmannode *rchild;

 13 }huffmannode, *phuffmannode;

 14 

 15 typedef struct _list

 16 {

 17     phuffmannode node;

 18     struct _list * next;

 19 }list, *plist;

 20 

 21 plist init_list()

 22 {

 23     plist head = (plist)malloc(sizeof(struct _list));

 24     head->next = head->node = NULL;

 25     return head;

 26 }

 27 

 28 void add_list(plist head, phuffmannode node)

 29 {

 30     plist insert = (plist)malloc(sizeof(struct _list));

 31     insert->node = node;

 32     insert->next = NULL;

 33     if(head==NULL)

 34         printf("head is null\n");

 35     if(head!=NULL)

 36     {

 37         plist pre = head;

 38         head = head->next;

 39         while(head!=NULL && node->data > head->node->data)

 40         {

 41             pre = head;

 42             head = head->next;

 43         }

 44         insert->next = pre->next;

 45         pre->next = insert;

 46     }

 47 }

 48 

 49 void display(plist head)

 50 {

 51     head = head->next;

 52     while(head!=NULL)

 53     {

 54         printf("%d ", head->node->data);

 55         head = head->next;

 56     }

 57     printf("\n");

 58 }

 59 

 60 phuffmannode get_list(plist head)

 61 {

 62     plist temp = head->next;

 63     phuffmannode top = head->next->node;

 64     head->next = head->next->next;

 65     free(temp);

 66     return top;

 67 }

 68 

 69 phuffmannode create_huffmannode(plist li)

 70 {

 71     phuffmannode lchild, rchild, node;

 72     if(li->next!=NULL && li->next->next == NULL)

 73         return get_list(li);

 74     while(li->next!=NULL && li->next->next!=NULL)

 75     {

 76         lchild = get_list(li);

 77         rchild = get_list(li);

 78         node = (phuffmannode)malloc(sizeof(struct _huffmannode));

 79         node->data = lchild->data + rchild->data;

 80         node->lchild  = lchild;

 81         node->rchild = rchild;

 82         add_list(li, node);

 83     }

 84     return get_list(li);

 85 }

 86 

 87 int traversetree(phuffmannode root, int level)

 88 {

 89     if(root==NULL)

 90         return 0;

 91     if(root->lchild==NULL && root->rchild==NULL)

 92         return root->data*level;

 93     return traversetree(root->lchild ,level+1) + traversetree(root->rchild, level+1);

 94 }

 95 

 96 void destorytree(phuffmannode root)

 97 {

 98     if(root==NULL)

 99         return;

100     if(root->lchild==NULL && root->rchild==NULL)

101     {

102         free(root);

103         root = NULL;

104         return;

105     }

106     destorytree(root->lchild);

107     destorytree(root->rchild);

108 }

109 

110 int main()

111 {

112     int count, i, data, level;

113     phuffmannode node;

114     level = 0;

115     plist head = init_list();

116     while(scanf("%d", &count)!=EOF)

117     {

118         for(i=0;i<count;i++)

119         {

120             scanf("%d", &data);

121             node = (phuffmannode)malloc(sizeof(struct _huffmannode));

122             node->data = data;

123             node->lchild = node->rchild = NULL;

124             add_list(head, node);

125         }

126         phuffmannode root = create_huffmannode(head);

127         printf("This huffman tree is value is:%d\n", traversetree(root, level));

128         destorytree(root);

129     }

130     return 0;

131 }

 上面是链表建树的办法，如果不建树，不用链表，仅仅为了完成这道题，今天看的方法真是帅呆了！

View Code

 1 #include <stdio.h>

 2 #include <stdlib.h>

 3 

 4 int val[1001];

 5 

 6 int cmp(const void * a,const void * b) //when the result is true "a>b" , a is after b

 7 {

 8     return *(int *)a - *(int *)b;

 9 }

10 

11 int main()

12 {

13     int n;

14     int i;

15     int ans;

16     while(scanf("%d",&n) != EOF)

17     {

18         ans = 0;

19         for(i = 0;i < n;i++) 

20             scanf("%d",&val[i]);

21         for(i = 1;i < n;i++)

22         {

23             qsort(&val[i - 1], n - i + 1, sizeof(val[0]), cmp);

24             ans += val[i - 1] + val[i];

25             val[i] += val[i - 1];

26         }

27         printf("%d\n",ans);

28     }

29     return 0;

30 }