HDU 5880 Family View

Posted 2020-08-09 Fighting Heart

$AC$自动机。

用$AC$自动机匹配一次，开一个$flag$记录一下以$i$位置为结尾的最长要打$*$多少个字符，然后倒着扫描一次就可以输出了。

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<bitset>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-6;
void File()
{
    freopen("D:\\in.txt","r",stdin);
    freopen("D:\\out.txt","w",stdout);
}
template <class T>
inline void read(T &x)
{
    char c=getchar(); x=0;
    while(!isdigit(c)) c=getchar();
    while(isdigit(c)) {x=x*10+c-‘0‘; c=getchar();}
}

const int maxn=1000010;
int flag[maxn];
char buf[maxn];

struct Trie
{
    int next[maxn][26],fail[maxn],end[maxn],Len[maxn];
    int root,L;
    int newnode()
    {
        for(int i = 0;i < 26;i++) next[L][i] = -1;
        Len[L]= end[L] = 0; L++;
        return L-1;
    }
    void init()
    {
        L = 0;
        root = newnode();
    }
    void insert(char buf[])
    {
        int len = strlen(buf);
        int now = root;
        for(int i = 0;i < len;i++)
        {
            if(next[now][buf[i]-‘a‘] == -1)
                next[now][buf[i]-‘a‘] = newnode();
            now = next[now][buf[i]-‘a‘];
        }
        end[now]++;
        Len[now]=strlen(buf);
    }
    void build()
    {
        queue<int>Q;
        fail[root] = root;
        for(int i = 0;i < 26;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 < 26;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 query(char buf[])
    {
        int len = strlen(buf);
        int now = root;
        int res = 0;
        for(int i = 0;i < len;i++)
        {
            int sign;
            if(buf[i]>=‘A‘&&buf[i]<=‘Z‘) sign=buf[i]-‘A‘;
            else if(buf[i]>=‘a‘&&buf[i]<=‘z‘) sign=buf[i]-‘a‘;
            else { now=root; continue; }
            now = next[now][sign];
            int temp = now;
            while( temp != root )
            {
                flag[i]=max(flag[i],Len[temp]);
                temp = fail[temp];
            }
        }
    }
};

Trie ac;

int main()
{
    int T,n; scanf("%d",&T);
    while( T-- )
    {
        scanf("%d",&n); ac.init();
        for(int i = 0;i < n;i++)
            { scanf("%s",buf); ac.insert(buf); }
        ac.build();

        getchar(); gets(buf); memset(flag,0,sizeof flag);
        ac.query(buf);

        int leng=strlen(buf); int num=0;

        for(int i=leng-1;i>=0;i--)
        {
            num=max(num,flag[i]);
            if(num==0) continue;
            else buf[i]=‘*‘, num--;
        }
        printf("%s\n",buf);
    }
    return 0;
}