【HDU】病毒侵袭持续中（AC自动机+map）

来源：互联网发布：数据分析经典案例分享编辑：程序博客网时间：2024/05/22 02:21

一开始一直WA，之后发现这道题不止一组输入，改成多组输入之后就过了。

利用map把每个字符串映射到它对应的结点上就行了。

119094672014-10-19 11:54:00Accepted3065234MS16912K2754 BG++KinderRiven

#include<queue>#include<map>#include<cstdio>#include<string>#include<vector>#include<cstring>#include<algorithm>using namespace std;const int maxn = 55555;const int max_size = 130;char ss[1111][55];map<string,int>vis;struct Trie{    int next[maxn][max_size];    int fail[maxn];    int  val[maxn];    int sz;    int root;    int num[maxn];    int index(char e){        return e - 31;    }    void init(){        sz = 0;        root = newnode();    }    int newnode(){        val[sz] = 0; num[sz] = 0;        memset(next[sz],-1,sizeof(next[sz]));        sz ++;        return sz - 1;    }    void insert(char *str){        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] = 1; //有单词        vis[string(str)] = u;    }    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{ //这个点是一个单词的结尾                   fail[next[now][i]] = next[fail[now]][i];                   q.push(next[now][i]);                }            }        }    }    void count(char *str){        int now = root;        int L = strlen(str);        for(int i = 0; i < L; i++){            int e = index(str[i]);            now = next[now][e];            int temp = now;            while(temp != root){                if(val[temp]){ //如果这个结点是个单词末尾                    num[temp] ++;                    //printf("%d\n",temp);                }                temp = fail[temp];            }        }    }};Trie ac;char _str[2222222];int main(){    int n;    while(scanf("%d",&n) != EOF){        ac.init();        vis.clear();        getchar();        for(int i = 0; i < n ; i ++){             gets(ss[i]);             ac.insert(ss[i]);        }        ac.build();        gets(_str);        ac.count(_str);        for(int i = 0; i < n; i++){            int t = vis[string(ss[i])];            if(ac.num[t]){                printf("%s: %d\n",ss[i],ac.num[t]);            }        }    }    return 0;}

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