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【HDU】病毒侵袭(AC自动机模板题)

AC自动机的模板题,由于输入的字符串中的字符不保证全为小写字母,所以范围应该在130之前,而前31位字符是不可能出现在字符串的(不懂得查下ACSII表就行了),所以只需要开的结点数组大小为130足够了,如果开256就会内存超限。

119087752014-10-19 10:45:38Accepted2896250MS29596K2760 BG++KinderRiven

输入只有一组,所以不用担心超时的问题。

#include<queue>
#include<cstdio>
#include<vector>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn = 111111;
const int max_size = 130;
const int maxd = 222;
vector<int>G[1111];
struct Trie{
    int next[maxn][max_size];
    int fail[maxn];
    int  val[maxn];
    int sz;
    int root;
    int index(char e){
        return e - 31;
    }
    void init(){
        sz = 0;
        root = newnode();
    }
    int newnode(){
        val[sz] = 0;
        memset(next[sz],-1,sizeof(next[sz]));
        sz ++;
        return sz - 1;
    }
    void insert(char *str,int pos){
        int L = strlen(str);
        int u = root;
        for(int i = 0; i < L; i++){
            int e = index(str[i]);
            if(next[u][e] == -1)
               next[u][e] = newnode();
           u = next[u][e];
        }
        val[u] = pos;
        //printf("%d %d\n",u,pos);
    }
    void build(){ //建立失配边
        fail[root] = root;
        queue<int>q;
        for(int i = 0; i < max_size; 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 < max_size; 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]);
                }
            }
        }
    }
    void count(char *str,int pos){
        int L = strlen(str);
        int u = root;
        for(int i = 0; i < L; i++){
            int e = index(str[i]);
            u = next[u][e];
            int temp = u;
            while(temp != root){
                if(val[temp] != 0)
                    G[pos].push_back(val[temp]);
                temp = fail[temp];
            }
        }
        return;
    }
};
Trie ac;
int main(){
    int n,m;
    ac.init();
    scanf("%d",&n);
    for(int i = 1; i <= n; i++){
        char str[maxd];
        scanf("%s",str);
        ac.insert(str,i);
    }
    //printf("%d\n",ac.sz);
    ac.build();
    scanf("%d",&m);
    for(int i  = 1; i <= m; i++){
        char str[maxn];
        scanf("%s",str);
        ac.count(str,i);
    }
    int cnt = 0;
    for(int i = 1; i <= m; i++)if(G[i].size()){
        sort(G[i].begin(),G[i].end());
        cnt ++;
        printf("web %d:",i);
        for(int j = 0; j < G[i].size(); j++)
            printf(" %d",G[i][j]);
        printf("\n");
    }
    printf("total: %d\n",cnt);
}

【HDU】病毒侵袭(AC自动机模板题)