字符串匹配Sunday算法

//
// 字符串匹配 sunday算法
#include <iostream>
#include <string.h>
#include <assert.h>
#include <time.h>
using namespace std;

const char * strMatch(const char *src, const char *need)
{
int Mlen=strlen(src);
int Nlen=strlen(need);
// 1.计算移动距离
size_t distance[256];
int i;
for (i=0; i<256; i++)
{
distance[i]=Nlen+1;
}
for (i=0; i<Nlen; i++)
{
distance[(unsigned char)need[i]]=Nlen-i;
}

//2.循环
int j;
i=0;
while (i < Mlen-Nlen+1)
{
j=0;
while(j<Nlen)
{
if (src[i]==need[j])
{
i++; j++;
continue;
}else
{
break;
}
}
if (j==Nlen) // 匹配成功
{
return src+i-j;
}else
{
i=i-j+distance[src[i-j+Nlen]];
}
}

return NULL;

}
int main()
{
char str1[]="abcdefghijk";
char str2[]="cdef";
char str3[]="cdeh";
const char *p;
if (p=strMatch(str1,str2))
{
cout<<str1<<"   find "<<str2<<"   result:"<<p<<endl;
}else
{
cout<<str1<<"   NOT FOUND  "<<str2<<endl;
}
p=NULL;
if (p=strMatch(str1,str3))
{
cout<<str1<<"   find "<<str3<<"   result:"<<p<<endl;
}else
{
cout<<str1<<"   NOT FOUND  "<<str3<<endl;
}

int TestN=100000000;
cout<<endl<<"性能测试  "<<TestN<<"次循环"<<endl;
time_t ib,ie;
int N=TestN;
ib=clock();
while (N--)
{
p=strstr(str1,str2);
}
ie=clock();
cout<<"strstr()  cost "<<ie-ib<<" ms "<<endl;

N=TestN;
ib=clock();
while (N--)
{
p=strMatch(str1,str2);
}
ie=clock();
cout<<"strMatch()  cost "<<ie-ib<<" ms "<<endl;

/////
N=TestN;
char str4[]="cbdsuhfailfhbuwgfqoefh geuihocurnoqrg wofyhwe8uoifruhhhhhhhhkgaosfyqpgpfhqpr h;ssssshttp://hi.baidu.com/yevqbqwaxdbdfmq/item/5f2fb8dfd0577748fa576852";
char str5[]="baidu.com/ye";
ib=clock();
while (N--)
{
p=strstr(str4,str5);
}
ie=clock();
cout<<"strstr()  cost "<<ie-ib<<" ms "<<endl;

N=TestN;
ib=clock();
while (N--)
{
p=strMatch(str4,str5);
}
ie=clock();
cout<<"strMatch()  cost "<<ie-ib<<" ms "<<endl;
return 0;
}