/*主函数里初始化和调用*/
/*next[0] = 0;
exkmp(s2+1,s2,next+1,next);
exkmp(s1,s2,ex,next);*/
/*扩展kmp算法可以用o(n+m)的复杂度求出字符串s1的任意后缀与字符串s2的最长公共前缀*/
/*扩展kmp算法的next[i]==j表示s2的以s2[i]为起始的后缀与串本身的最长公共前缀长度*/
/*ex[i]为s1[i..]与s2的最长公共前缀，next[i]为s2[i..]与s2的最长公共前缀*/
void exkmp(char s1[],char s2[],int ex[],int next[])
{
int i,j,p;
i = j = 0;
p = -1;
while(s1[i]!=' ')
{
if( p == -1)
{
j = 0;
do
p++;
while(s1[i+p] != ' '&&s1[i+p] == s2[j+p]);
ex[i] = p;
}
else if(next[j] < p)
ex[i] = next[j];
else if(next[j] > p)
ex[i] = p;
else
{
j = 0;
while(s1[i+p] != ' '&&s1[i+p] == s2[j+p])
p++;
ex[i] = p;
}
i++;
j++;
p--;
}
ex[i] = 0;
return;
}