再写KMP算法

#include<iostream>
#include<string>
using namespace std;

void getNext(char const*T,int len,int *next)
{
    int i =0,j=-1;
    next[i] = -1;
    while(i<len)
    {
        if(j == -1 || T[i] == T[j])
        {
            i++;j++;next[i] =j;
        }
        else
            j = next[j];
    }
}
int KMP_search(char const*S,int slen,char const*T,int tlen,int *next)
{
    int i=0,j=0;
    while(i<slen && j<tlen)
    {
        if(j==-1 || T[j] == S[i])
        {
            j++;i++;
        }
        else
            j=next[j];
    }
    return i-tlen;
}

int main()
{
    string S="aabcabcebafabcabceabcaefabcacdabcab";
    string T ="abac";
    int *next = new int[T.size()];
    getNext(T.data(),T.size(),next);
    for(int i = 0;i<T.size();i++)
        cout<<next[i]<<" ";
    cout<<endl;

    cout<<"The subString start with :";
    cout<<KMP_search(S.data(),S.size(),T.data(),T.size(),next)<<endl;
    return 0;
}

【参见】http://blog.csdn.net/yaochunnian/article/details/7059486