• huffman


    今天试着做了个Huffman,结果压缩算法被硬生生写成膨胀算法

    我好蒻啊!!!!!!!!!!!!!!!

    加密:

     1 #include<bits/stdc++.h>
     2 #include<windows.h>
     3 #define ll long long
     4 #define N 10000001
     5 using namespace std;
     6 int cnt;
     7 struct node{
     8     int l,r,val;
     9     char ch;
    10 }hfm[N];
    11 
    12 struct cmp{bool operator()(int a,int b){return hfm[a].val>hfm[b].val;}};
    13 
    14 char a[128],b[128],str[N];
    15 int tohfm[256],len,root,cdl[256];
    16 bitset<8>code[256];
    17 bool apr[256];
    18 priority_queue<int,vector<int>,cmp>q;
    19 
    20 void dfs(int x,int dep,int cd){
    21     if(hfm[x].ch){
    22         int ascii=(int)hfm[x].ch;
    23         cdl[ascii]=dep;
    24         for(int i=dep-1;i>=0;i--)
    25             code[ascii][i]=cd&1,cd>>=1;
    26         return;
    27     }
    28     dfs(hfm[x].l,dep+1,cd<<1);
    29     dfs(hfm[x].r,dep+1,cd<<1|1);
    30 }
    31 
    32 void huffman(){
    33     for(int i=1;i<=cnt;i++)q.push(i);
    34     while(q.size()>=2){
    35         int a,b,c;
    36         a=q.top(),q.pop();
    37         b=q.top(),q.pop();
    38         c=++cnt;
    39         hfm[c].l=a,hfm[c].r=b,hfm[c].val=hfm[a].val+hfm[b].val;
    40         q.push(c);
    41     }
    42     dfs(root=cnt,0,0);
    43 }
    44 
    45 void Out(int x){
    46     char ch[16]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
    47     printf("%c%c",ch[x/16],ch[x%16]);
    48 }
    49 
    50 int main(){
    51     scanf("%s%s",a,b);
    52     freopen(a,"r",stdin);
    53     freopen(b,"w",stdout);
    54     while(~scanf("%c",&str[++len])){
    55         int ascii=(int)str[len];
    56         if(!apr[ascii])
    57             tohfm[ascii]=++cnt,apr[ascii]=true,hfm[cnt].ch=str[len];
    58         hfm[tohfm[ascii]].val++;
    59     }
    60     int cnt1=cnt;
    61     huffman();
    62     Out(cnt1);
    63     for(int i=1;i<=cnt1;i++){
    64         int ascii=(int)hfm[i].ch;
    65         Out(ascii);
    66         int ans=1;
    67         for(int j=0;j<cdl[ascii];j++)ans=ans<<1|code[ascii][j];
    68         Out(ans);
    69     }
    70     int tail=0,ans=0;
    71     for(int i=1;i<=len;i++){
    72         int ascii=(int)str[i];
    73         for(int j=0;j<cdl[ascii];j++){
    74             tail++;
    75             ans=ans<<1|code[ascii][j];
    76             if(tail==7){
    77                 Out(ans);
    78                 tail=0,ans=0;
    79             }
    80         }
    81     }
    82     if(tail)
    83     Out(ans<<(7-tail));
    84     return 0;
    85 }

    解密:

     1 #include<bits/stdc++.h>
     2 #include<windows.h>
     3 #include<conio.h>
     4 #define ll long long
     5 #define N 100001
     6 using namespace std;
     7 char hfm[1024],a[128],b[128];
     8 int n;
     9 
    10 int In(){
    11     int re=0;
    12     char a,b;
    13     if(!~scanf("%c%c",&a,&b))return -1;
    14     re=(a<='9'?a-'0':a-'A'+10);
    15     re=re<<4|(b<='9'?b-'0':b-'A'+10);
    16     return re;
    17 }
    18 
    19 int main(){
    20     scanf("%s%s",a,b);
    21     freopen(a,"r",stdin);
    22     freopen(b,"w",stdout);
    23     n=In();
    24     for(int i=1;i<=n;i++){
    25         int ch,code;
    26         ch=In();
    27         code=In();
    28         hfm[code]=(char)ch;
    29 //        printf("%c : %d
    ",ch,code);
    30     }
    31     int byte,last;
    32     int val=1;
    33     while(~(byte=In())){
    34         for(int i=6;i>=0;i--){
    35             val=val<<1|((byte&(1<<i))>>i);
    36             if(hfm[val]){
    37                 if(hfm[val]&(1<<7))
    38                     if(!last)last=hfm[val];
    39                     else printf("%s",last<<8|(hfm[val])),last=0;
    40                 else printf("%c",hfm[val]);
    41                 val=1;
    42             }
    43         }
    44     }
    45     return 0;
    46 }

    BUG很多,可行性很低,我很蒻

    但是可以用来加密(雾)

    其实就是模板改了一下

    2018-12-12:

    在11月份的的时候做出了真正的huffman压缩

    今天突然想起发过这篇文章

    于是来贴个代码

    压缩:

      1 #include<bits/stdc++.h>
      2 #include<fstream>
      3 #define ll long long
      4 #define N 10000001
      5 #define code(a,b) get(code[a],b)
      6 #define Out(x,y) output.write((char*)&x,y)
      7 using namespace std;
      8 int cnt;
      9 struct node{
     10     int l,r,val;
     11     char ch;
     12 }hfm[N];
     13 
     14 char a[128],b[128],str[N];
     15 int tohfm[512],len,root,cdl[512];
     16 int code[1024];
     17 bool apr[1024];
     18 
     19 struct cmp{bool operator()(int a,int b){return hfm[a].val>hfm[b].val;}};
     20 
     21 priority_queue<int,vector<int>,cmp>q;
     22 
     23 void dfs(int x,int dep,int cd){
     24     if(!x)return;
     25     if(hfm[x].ch){
     26         int ascii=hfm[x].ch;
     27         cdl[ascii]=dep;
     28         code[ascii]=cd;
     29         return;
     30     }
     31     dfs(hfm[x].l,dep+1,cd<<1);
     32     dfs(hfm[x].r,dep+1,cd<<1|1);
     33 }
     34 
     35 void huffman(){
     36     for(int i=1;i<=cnt;i++)q.push(i);
     37     while(q.size()>=2){
     38         int a,b,c;
     39         a=q.top(),q.pop();
     40         b=q.top(),q.pop();
     41         c=++cnt;
     42         hfm[c].l=a,hfm[c].r=b,hfm[c].val=hfm[a].val+hfm[b].val;
     43         q.push(c);
     44     }
     45     if(cnt==1)code[(unsigned)hfm[1].ch]=2,cdl[(unsigned)hfm[1].ch]=1;
     46     else dfs((root=cnt),0,1);
     47 }
     48 
     49 int get(int a,int b){return (a&(1<<(8-b)))>>(8-b);}
     50 
     51 int main(){
     52     scanf("%s%s",a,b);
     53     ofstream output(b,ios::out|ios::binary);
     54     FILE* file = fopen(a, "rb");
     55     fseek(file,0,SEEK_END);
     56     len=ftell(file);
     57     fclose(file);
     58     ifstream input(a,ios::in|ios::binary);
     59     input.read((char*)&str,len);
     60     for(int i=0;i<len;i++){
     61         if(!apr[(int)str[i]])
     62             tohfm[(int)str[i]]=++cnt,apr[(int)str[i]]=true,hfm[cnt].ch=str[i];
     63         hfm[tohfm[(int)str[i]]].val++;
     64     }
     65     int Len=len;
     66     input.close();
     67     int cnt1=cnt;
     68     huffman();
     69     Out(cnt1,4);
     70     Out(Len,4);
     71     printf("%d %d
    ",cnt1,Len);
     72     for(int i=1;i<=cnt1;i++){
     73         int ascii=(int)hfm[i].ch;
     74         Out(hfm[i].ch,1);
     75         printf("%c %d ",ascii,cdl[ascii]);
     76         int ans=code[ascii];
     77         Out(ans,1);
     78         for(int j=1;j<=8;j++)printf("%d",code(ascii,j));
     79         puts("");
     80     }
     81     int tail=0,ans=0;
     82     for(int i=0;i<Len;i++){
     83         int ascii=(int)str[i];
     84         //printf("%d  ",code[ascii]);
     85         for(int j=8-cdl[ascii]+1;j<=8;j++){
     86             tail++;
     87             ans=ans<<1|code(ascii,j);
     88             if(tail==8){
     89                 for(int j=1;j<=8;j++)printf("%d",get(ans,j));
     90                 //printf("%d  ",ans);
     91                 Out(ans,1);
     92                 tail=0,ans=0;
     93             }
     94         }
     95     }
     96     puts("");
     97     if(tail)ans<<=(8-tail),Out(ans,1);
     98     output.close();
     99     return 0;
    100 }
    101 /*
    102  1.txt
    103  2.txt
    104 */

    解压:

     1 #include<bits/stdc++.h>
     2 #include<fstream>
     3 #define ll long long
     4 #define N 10000001
     5 #define In(x,y) input.read((char*)&x,y)
     6 #define Out(x,y) output.write((char*)&x,y)
     7 using namespace std;
     8 char a[128],b[128],hfm[(1<<16)-1];
     9 int n,len;
    10 int get(int a,int b){return (a&(1<<(8-b)))>>(8-b);}
    11 int main(){
    12     scanf("%s%s",a,b);
    13     ifstream input(a,ios::in|ios::binary);
    14     ofstream output(b,ios::out|ios::binary);
    15     In(n,4),In(len,4);
    16     printf("N=%d Len=%d
    ",n,len);
    17     for(int i=1;i<=n;i++){
    18         char ch;
    19         int code=0;
    20         In(ch,1),In(code,1);
    21         printf("%c : %d
    ",ch,(int)code);
    22         hfm[(int)code]=ch;
    23     }
    24     int byte;
    25     int val=1;
    26     while(len){
    27         byte=0;
    28         In(byte,1);
    29         for(int i=1;i<=8;i++){
    30             val=val<<1|get(byte,i);
    31             if(hfm[val]){
    32                 len--;
    33                 Out(hfm[val],1);
    34                 printf("%c",hfm[val]);
    35                 val=1;
    36             }
    37             if(!len)break;
    38         }
    39     }
    40     return 0;
    41 }
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  • 原文地址:https://www.cnblogs.com/nlKOG/p/9822383.html
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