我写的KMP 算法

类别:VC语言 点击:0 评论:0 推荐:

#include<iostream>
#include<time.h>
#include<string>
using namespace std;
void init(string ,string);
void show(char [],int);
int kmp(string ,string,int pos);
void get_next(char*,int *);
string s1,t1;
int m,n;
char *s;
char *t;
int *next;
/*************************MAIN**************************************/
int main(int argc[],char*args[])
{
   
 double t=clock();
 cout<<"找到位置为:"<<kmp("acbsabcaacabaabaabcacaabc","abaabca",1)<<endl;
    delete[] s;
 delete[] next;
 cout<<"耗时:"<<(clock()-t)/1000<<"毫秒!"<<endl;
 return 0;
}  
/**********************++++NEXT++++********************************/
void get_next(char s[],int ne[])
{
    ne =new int[n+1];
    next=new int[n+1];
    ne[0]=9999;
    int i(1),j(0);
    ne[1]=0;
    while(i<=(int)(t[0]))//数组是字符型的,要转化为整数
 {
     if(j==0||t[i]==t[j]){++i;++j;ne[i]=j;}
     else j=ne[j];
 }
   for( i=1;i<=n;i++)
   {
   cout<<"next["<<i<<"]="<<ne[i]<<endl;
      next[i]=ne[i];
   }
}
/********************++++KMP+++**********************************/
  int kmp(string s0,string t0,int pos)
  {
        init(s0,t0);
        int i=pos,j=1;
        while(i<=((int)(s[0]))&&(j<=((int)(t[0]))))
  {
         if((j==0)||(s[i]==t[j])){++i;++j;}
      else j=next[j];
        
  }
        if(j>(int)(t[0])) return i-((int)(t[0]));
        else return 0;

  }
/***************++++INIT+++*****************************************/
    void init(string ss,string tt)
 {
       //cout<<"请输入原串S=: "<<endl;
       //cin>>s1;
       //cout<<"请输入模式串T=:"<<endl;
       //cin>>t1;
       s1=ss;
       t1=tt;
       m=s1.length();
       n=t1.length();
       //if((s=(char*)malloc((m+1)*sizeof(char)))<0){cout<<"failed\n";return;}
       s=new char[m+1];
       s[0]=m;
       //if((t=(char*) malloc((n+1)*sizeof(char)))<0) {cout<<"failed\n";return;}
       t=new char[n+1];
       t[0]=n;
       for(int i=1;i<=m;i++)
      s[i]=s1.at(i-1);
       for( i=1;i<=n;i++)
         t[i]=t1.at(i-1);
        cout<<"原串为: ";    show(s,m);
     cout<<"模式串为: ";  show(t,n);
        get_next(t,next);
 }
/*******************++++SHOW+++**************************************/
       void show(char s[],int n )
    {
         for(int i=1;i<=n;i++)
         cout<<s[i]<<"  ";
         cout<<endl;
         cout<<"长度为: "<<int(s[0])<<"\n";
    }

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