自写KMP模板

int* Getnext(char *p,int len_p){//p为模式串 
    int *Next = new int[len_p];
    Next[0] = -1;
    int j = -1,i=0;
    while(i < len_p){//自身与自身匹配 
        while(j != -1&&p[j]!=p[i])//移动匹配串 
            j = Next[j];
        j+=1;
        Next[++i] = j; 
    }
    return Next;
}
vector<int>* Kmp(char *s,char *p,int len_s,int len_p){//s为主串,p为匹配串 
    int *Next = Getnext(p,len_p);//求得Next数组    
    int j = 0;//j为匹配串匹配到的位置
    vector<int>* ans = new vector<int>();//ans为匹配到的主串的开头下标位置 
    for(int i=0;i < len_s;i++){
        while(j != -1 && s[i] != p[j])
            j = Next[j];
        j+=1;
        if(j == len_p){//匹配串匹配完毕
            ans->push_back(i - len_p + 1);
            j = Next[j];//j退回到Next[j] 
        }
    } 
    return ans;
}