HDU 3065：病毒侵袭持续中（AC自动机）

http://acm.hdu.edu.cn/showproblem.php?pid=3065

题意：中文题意。

思路：直接插入然后用一个数组记录id和cnt，因为n只有1000，可以开一个数组判断第几个字符串出现过的次数，然后输出就好了。

坑点：多组输入！！！然后因为new出来的空间要自己释放，因此需要用一个vector装起来（似乎多此一举），最后delete掉。

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
#define N 1010
#define M 2000010
#define TOL 128
typedef struct Node {
    Node* next[TOL];
    Node* fail;
    int id, cnt;
    Node () {
        for(int i = 0; i < TOL; i++) next[i] = NULL;
        id = cnt = 0;
        fail = NULL;
    }
} node;

char s[N][55], str[M];

class AC_DFA {

private:
    node* root;
    int ans[N], n;
    vector<node*> dic;

public:
    AC_DFA(int now) {
        dic.clear();
        root = new Node();
        dic.push_back(root);
        n = now;
        memset(ans, 0, sizeof(ans));
    }

    ~AC_DFA() {
        for(int i = 0; i < dic.size(); i++) delete dic[i];
    }

    void insert(char *s, int id) {
        int len = strlen(s);
        node* now = root;
        for(int i = 0; i < len; i++) {
            char c = s[i];
            if(now->next[c] == NULL) now->next[c] = new Node(), dic.push_back(now->next[c]);
            now = now->next[c];
        }
        now->id = id;
        now->cnt++;
    }

    void build() {
        queue<node *> que;
        que.push(root);
        root->fail = NULL;
        while(!que.empty()) {
            node* now = que.front();
            que.pop();
            for(int i = 0; i < TOL; i++) {
                if(now->next[i]) {
                    node* p = now->fail;
                    while(p && p->next[i] == NULL) p = p->fail;
                    if(p) now->next[i]->fail = p->next[i];
                    else now->next[i]->fail = root;
                    que.push(now->next[i]);
                } else {
                    if(now == root) now->next[i] = root;
                    else now->next[i] = now->fail->next[i];
                }
            }
        }
    }

    void match(char *s) {
        int len = strlen(s);
        node *now = root, *p;
        for(int i = 0; i < len; i++) {
            char c = s[i];
            while(now != root && now->next[c] == NULL)
                now = now->fail;
            now = now->next[c];
            p = now;
            while(p) {
                if(p->cnt) ans[p->id] += p->cnt;
                p = p->fail;
            }
        }
    }

    void print() {
        for(int i = 1; i <= n; i++)
            if(ans[i]) printf("%s: %d
", s[i], ans[i]);
    }

};

int main() {
    int n;
    while(~scanf("%d", &n)) {
        AC_DFA ac(n);
        for(int i = 1; i <= n; i++) {
            scanf("%s", s[i]);
            ac.insert(s[i], i);
        }
        scanf("%s", str);
        ac.build();
        ac.match(str);
        ac.print();
    }
    return 0;
}