AC自动机

题目要求：输入n个单词，然后输入一段字符串，请问字符串中第几个位置第一次出现了该单词。

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <queue>
using namespace std;
char str[1010][100];
int ans;
struct Trie
{
    int next[1010*50][258],fail[1010*50],end[1010*50];
    int root,L;
    int newnode()
    {
        for(int i = 0;i < 258;i++)
            next[L][i] = -1;
        end[L++] = -1;
        return L-1;
    }
    void init()
    {
        L = 0;
        root = newnode();
    }
    void insert(char s[],int id)
    {
        int len = strlen(s);
        int now = root;
        for(int i = 0;i < len;i++)
        {
            if(next[now][s[i]] == -1)
                next[now][s[i]] = newnode();
            now = next[now][s[i]];
        }
        end[now] = id;
    }
   void build()
    {
        queue<int>Q;
        fail[root] = root;
        for(int i = 0;i < 128;i++)
            if(next[root][i] == -1)
                next[root][i] = root;
            else
            {
                fail[next[root][i]] = root;
                Q.push(next[root][i]);
            }
        while(!Q.empty())
        {
            int now = Q.front();
            Q.pop();
            for(int i = 0;i < 258;i++)
                if(next[now][i] == -1)
                    next[now][i]=next[fail[now]][i];
                else
                {
                    fail[next[now][i]]=next[fail[now]][i];
                    Q.push(next[now][i]);
                }
        }
    }
    int num[1010];
    void query(char buf[],int n)
    {
        int count=0;
        for(int i = 0;i < n;i++)
            num[i] = 0;
        int len=strlen(buf);
        int now=root;
        for(int i=0;i<len;i++)
        {
            if(buf[i]==' ')
                count++;
            now=next[now][buf[i]];
            int temp = now;
            while( temp != root )
            {
                if(end[temp] != -1&&num[end[temp]]==0)
                    num[end[temp]]=count;
                temp = fail[temp];
            }
        }
       for(int i = 0;i < n;i++)
            if(num[i] > 0)
                printf("%s: %d
",str[i],num[i]);
    }

};

char buf[2000010];
Trie ac;
int main()
{
    int n;
    while(scanf("%d",&n) == 1)
    {
        ans=0;
        ac.init();
         getchar();
        for(int i=0;i<n;i++)
        {
            gets(str[i]);
            ac.insert(str[i],i);
        }
        ac.build();
        gets(buf);
        ac.query(buf,n);
    }
    return 0;
}