优先队列优化哈夫曼编码

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前言

个人小记

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一、代码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#define MAX_NODE 80
#define MAX_STR 50
#define MAX_HEAP 100
#define father(i) ((i)/2)
#define left(i)   ((i)*2)
#define right(i)  ((i)*2+1)typedef struct Node
{int f;char ch;struct Node *lchild,*rchild;
}Node;typedef struct Heap
{int count,size;Node** __data,**data;
}Heap;void swap(Node** a,Node** b)
{Node* t=*a;*a=*b;*b=t;return ;
}void down_update(Heap*,int);Heap* init_heap(int n)
{Heap* h=(Heap*)malloc(sizeof(Heap));h->count=0;h->size=n;h->__data=(Node**)malloc(sizeof(Node*)*n);h->data=h->__data-1;return h;
}int isempty(Heap *h)
{return h->count==0;
}int isfull(Heap* h)
{return h->count==h->size;
}void up_update(Heap* h,int i)
{while(i>1&&h->data[i]->f<h->data[father(i)]->f){swap(&(h->data[i]),&(h->data[father(i)]));i=father(i);}return ;
}int push(Heap* h,Node* node)
{if(isfull(h)){printf("堆已满,无法压入\n");return 0;}h->data[++h->count]=node;up_update(h,h->count);return 1;
}Node* top(Heap* h)
{if(isempty(h)){printf("堆空,无法查看\n");return 0;}return h->data[1];
}int pop(Heap* h)
{if(isempty(h)){printf("堆空,无法弹出\n");return 0;}h->data[1]=h->data[h->count--];down_update(h,1);return 1;
}void down_update(Heap* h,int i)
{while(left(i)<=h->count){int min=i,l=left(i),r=right(i);if(h->data[min]->f>h->data[l]->f)min=l;if(right(i)<=h->count&&h->data[min]->f>h->data[r]->f)min=r;if(i==min)break;swap(&(h->data[i]),&(h->data[min]));i=min;}return ;
}Node* init_node(char ch,int f)
{Node* node=(Node* )malloc(sizeof(Node));node->f=f;node->ch=ch;node->lchild=node->rchild=NULL;return node;
}
int fc=0;
Node** init_arr(int n,int* s)
{fc=0;Node** arr=(Node**)malloc(sizeof(Node*)*n);for(int i=0;i<n;i++) arr[i]=(Node*)malloc(sizeof(Node));for(int i=0;i<256;i++){if(s[i]!=0){Node* node=init_node((char)i,s[i]);arr[fc]=node;fc++;}}return arr;
}void clear_tree(Node* root)
{if(root==NULL)return ;clear_tree(root->lchild);clear_tree(root->rchild);free(root);return ;
}int* count(char str[],int n)
{int *s=(int*)malloc(sizeof(int)*256);for(int i=0;i<256;i++)s[i]=0;for(int i=0;i<n;i++)s[(int)str[i]]+=1;return s;
}Node* CLO_build_halfman_tree(Node** arr,Heap* h,int n)
{for(int i=0;i<n-1;i++){Node* node1=top(h);pop(h);Node* node2=top(h);pop(h);Node* new_node=init_node('0',node1->f+node2->f);new_node->lchild=node1;new_node->rchild=node2;push(h,new_node);arr[n-i-2]=new_node;}return arr[0];
}void clear_heap(Heap* h)
{if(h==NULL)return ;free(h->__data);free(h);return ;
}void halfman_coding(Node* root,char buff[],int k)
{buff[k]=0;if(root->lchild==NULL&&root->rchild==NULL){printf("%c:%s\n",root->ch,buff);return ;}buff[k]='0';halfman_coding(root->lchild,buff,k+1);buff[k]='1';halfman_coding(root->rchild,buff,k+1);return ;
}int main()
{char str[MAX_STR];// scanf("%[^/n]",str);printf("请输入字符串:");fgets(str,MAX_STR,stdin);//s[strcspn(s,'\n')]=0;char *newline = strchr(str, '\n');if (newline != NULL) *newline = '\0';int* s=count(str,strlen(str));Node** arr=init_arr(MAX_NODE,s);Heap* h=init_heap(MAX_HEAP);for(int i=0;i<fc;i++)push(h,arr[i]);//压入堆Node* root=CLO_build_halfman_tree(arr,h,fc);char buff[MAX_STR];halfman_coding(root,buff,0);clear_tree(root);clear_heap(h);return 0;
}

二、测试结果

请输入字符串:aaaaabbccd
a:0
c:10
d:110
b:111

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