lzw_yima.cpp

LZW算法 LZW算法

#include<iostream>
#include<string>
#include<map>
using namespace std;
map<string,string> pos;
string bb[4097]={"#0","#1","#2","#3","#4","#5","#6","#7","#8","#9","#10","#11","#12","#13","#14",
        "#15","#16","#17","#18","#19","#20","#21","#22","#23","#24","#25","#26","#27","#28","#29","#30","#31"};
string b[4097]={"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t",
        "u","v","w","x","y","z","A","B","C","D","E","F"};
void strtab()
{
        for(int i=0;i<=3;i++)
           pos[bb[i]]=b[i];   
}   
string int2str( int num)
  {
    if (num == 0 )
       return " 0 " ;          
    string str = "" ;
    while (num)
    {
       str = ( char )(num % 10 + 48 ) + str;
       num /= 10 ;
    } 
    return str;
} 
int main()
{
    // freopen("in.txt","r",stdin);
   //  freopen("rn.txt","w",stdout);
     string data,code,old,temp;
     int i,j,mk[1000],k,l;
     string codestream[500];
     strtab();
    
     while(cin>>data)
     {
              basic_string<char>::iterator ie;
              for(l=0,i=0,ie=data.begin();ie!=data.end();i++,ie++)
                 if(*ie=='#')
                     { mk[l++]=i;
                       cout<<i;
                     }  
                     mk[l]=i;
             k=0;
             code.assign(data,mk[0],mk[1]-mk[0]);
             cout<<code<<endl;
             codestream[k++]=pos[code];
             old=code;
             code.assign(data,mk[1],mk[2]-mk[1]);
             cout<<code<<endl;
            //out<<"fsdf"<<code<<endl<<"fdsf";
             j=4,i=2;
             system("pause");
             while(1)
             {
               
                temp.erase();
                if(pos[code]!="")
                {
                       codestream[k++]=pos[code];
                       //cout<<"codestream="<<codestream[k-1]<<endl;
                       temp=pos[old];
                       temp+=*pos[code].begin();
                       //cout<<"temp="<<temp<<endl;
                       string s="#"+int2str(j++);
                       //cout<<"s="<<s<<endl;
                       pos[s]=temp;
                       old=code;
                      //  system("pause");
                }
                else 
                {
                       temp=pos[old];
                       temp+=*pos[code].begin();  
                       //cout<<"temp="<<temp<<endl;
                       codestream[k++]=temp;
                       
                       //cout<<"codestream="<<codestream[k-1]<<endl;
                       string s="#"+int2str(j++);
                       //cout<<"s="<<s<<endl;
                       pos[s]=temp;
                       old=code;
                       // system("pause");
                }
                if(i==l) break;
                code.assign(data,mk[i++],mk[i]-mk[i-1]);
            }
            printf("***\n");
             for(i=0;i<k;i++)
                      cout<<" "<<codestream[i];
                      printf("\nasdfa\n");
   }   
     system("pause");
    
    
         
}