HDU 2896：病毒侵袭（AC自动机）

http://acm.hdu.edu.cn/showproblem.php?pid=2896

题意：中文题意。

思路：AC自动机模板题。主要在于字符有128种，输出还要排序和去重！

注意是“total”不是“totol”！！！因为这个Debug了好久。

还有结点是new的，不然MLE。

主要用来测试模板，看了两个，发现没有注释掉的效率高点。

#include <cstring>
#include <algorithm>
#include <cstdio>
#include <vector>
#include <queue>
using namespace std;
#define N 100010
#define TOL 128

typedef struct Node {
    Node* next[TOL];
    Node* fail;
    int id;
    Node() {
        for(int i = 0; i < TOL; i++) next[i] = NULL;
        fail = NULL; id = 0;
    }
} node;

class AC_DFA {

    private:
        int ans;
        node *root;

    public:
        AC_DFA() {
            ans = 0; root = new Node();
        }

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

        void build() {
            root->fail = NULL;
            queue<node*> que;
            que.push(root);
            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 id) {
            bool flag = 0;
            int len = strlen(s);
            vector<int> tol;
            node* now = root; node* p;
            for(int i = 0; i < len; i++) {
                char c = s[i];
                while(now->next[c] == NULL && now != root) now = now->fail;
                now = now->next[c];
                p = now;
                while(p) {
                    if(p->id) tol.push_back(p->id), flag = 1;
                    p = p->fail;
                }
                /*
                char c = s[i];
                now = now->next[c];
                p = now;
                while(p) {
                    if(p->id) tol.push_back(p->id), flag = 1;
                    p = p->fail;
                }
                */
            }

            if(!flag) return ;
            sort(tol.begin(), tol.end());
            int cnt = unique(tol.begin(), tol.end()) - tol.begin(); // 去重
            ans++;
            printf("web %d: ", id);
            for(int i = 0; i < cnt; i++) {
                printf("%d", tol[i]);
                if(i == cnt - 1) putchar('
');
                else putchar(' ');
            }
        }

        void print() {
            printf("total: %d
", ans); // 不是totol
        }

};

int main() {

    AC_DFA ac;
    char s[10010];
    int n; scanf("%d", &n);
    for(int i = 1; i <= n; i++) {
        scanf("%s", s); ac.insert(s, i);
    }
    ac.build();
    int m; scanf("%d", &m);
    for(int i = 1; i <= m; i++) {
        scanf("%s", s); ac.match(s, i);
    }
    ac.print();
    return 0;
}