BZOJ 3940 Censoring ( Trie 图 )

题目链接

题意 : 中文题、点链接

分析 :

直接建 Trie 图、在每一个串的末尾节点记录其整串长度、方便删串操作

然后对于问询串、由于可能有删串操作

所以在跑 Trie 图的过程当中需要拿个栈记录一下路径

跑 Trie 图的意思就是说将问询串字符一个个拿出来

然后一直找当前节点的下一个对应字母的节点

由于是 Trie 图、所以在 Fail 的时候也会自动跑到对应的节点

这和普通的 AC 自动机不一样、在 Fail 的时候要每次暴力跳 Fail 节点

然后直接模拟即可

#include<bits/stdc++.h>
#define LL long long
#define ULL unsigned long long

#define scl(i) scanf("%lld", &i)
#define scll(i, j) scanf("%lld %lld", &i, &j)
#define sclll(i, j, k) scanf("%lld %lld %lld", &i, &j, &k)
#define scllll(i, j, k, l) scanf("%lld %lld %lld %lld", &i, &j, &k, &l)

#define scs(i) scanf("%s", i)
#define sci(i) scanf("%d", &i)
#define scd(i) scanf("%lf", &i)
#define scIl(i) scanf("%I64d", &i)
#define scii(i, j) scanf("%d %d", &i, &j)
#define scdd(i, j) scanf("%lf %lf", &i, &j)
#define scIll(i, j) scanf("%I64d %I64d", &i, &j)
#define sciii(i, j, k) scanf("%d %d %d", &i, &j, &k)
#define scddd(i, j, k) scanf("%lf %lf %lf", &i, &j, &k)
#define scIlll(i, j, k) scanf("%I64d %I64d %I64d", &i, &j, &k)
#define sciiii(i, j, k, l) scanf("%d %d %d %d", &i, &j, &k, &l)
#define scdddd(i, j, k, l) scanf("%lf %lf %lf %lf", &i, &j, &k, &l)
#define scIllll(i, j, k, l) scanf("%I64d %I64d %I64d %I64d", &i, &j, &k, &l)

#define lson l, m, rt<<1
#define rson m+1, r, rt<<1|1
#define lowbit(i) (i & (-i))
#define mem(i, j) memset(i, j, sizeof(i))

#define fir first
#define sec second
#define VI vector<int>
#define ins(i) insert(i)
#define pb(i) push_back(i)
#define pii pair<int, int>
#define VL vector<long long>
#define mk(i, j) make_pair(i, j)
#define all(i) i.begin(), i.end()
#define pll pair<long long, long long>

#define _TIME 0
#define _INPUT 0
#define _OUTPUT 0
clock_t START, END;
void __stTIME();
void __enTIME();
void __IOPUT();
using namespace std;
const int max_node = 2e5 + 10;
const int max_len = 2e5 + 10;
const int Letter  = 26;

char ans[max_len];
int pos[max_len];
int top = 0;

struct Aho{
    struct StateTable{
        int nxt[Letter];
        int fail, cnt, len;
        bool vis;
        void init(){
            memset(nxt, 0, sizeof(nxt));
            fail = 0;
            cnt = 0;
            len = 0;
            vis = false;
        }
    }Node[max_node];

    int sz;
    queue<int> que;

    inline void init(){ while(!que.empty())que.pop(); Node[0].init(); sz = 1; }

    inline void insert(char *s, int len){
        int now = 0;
        for(int i=0; i<len; i++){
            int idx = s[i] - 'a';
            if(!Node[now].nxt[idx]){
                Node[sz].init();
                Node[now].nxt[idx] = sz++;
            }
            now = Node[now].nxt[idx];
        }
        Node[now].len = len;
        Node[now].cnt++;
    }

    inline void build(){
        Node[0].fail = -1;
        que.push(0);
        while(!que.empty()){
            int top = que.front();  que.pop();
            for(int i=0; i<Letter; i++){
                if(Node[top].nxt[i]){
                    if(top == 0) Node[ Node[top].nxt[i] ].fail = 0;
                    else{
                        int v = Node[top].fail;
                        while(v != -1){
                            if(Node[v].nxt[i]){
                                Node[ Node[top].nxt[i] ].fail = Node[v].nxt[i];
                                break;
                            }v = Node[v].fail;
                        }if(v == -1) Node[ Node[top].nxt[i] ].fail = 0;
                    }que.push(Node[top].nxt[i]);
                }else Node[top].nxt[i] = top!=0?Node[ Node[top].fail ].nxt[i]:0;
            }
        }
    }

//    int Match(char *s){
//        int now = 0, res = 0;
//        for(int i=0; s[i]!=''; i++){
//            int idx = s[i] - 'a';
//            now = Node[now].nxt[idx];
//            int tmp = now;
//            while(tmp != 0 && !Node[tmp].vis){
//                res += Node[tmp].cnt;
//                Node[tmp].vis = true;
//                Node[tmp].cnt = 0;
//                tmp = Node[tmp].fail;
//            }
//        }
//        return res;
//    }

    void query(char * s){
        int len = strlen(s);
        int now = 0;
        pos[now] = now;
        for(int i=0; i<len; i++){
            int idx = s[i] - 'a';
            now = Node[now].nxt[idx];
            pos[++top] = now;
            ans[  top] = s[i];
            if(Node[now].len != 0){
                top -= Node[now].len;
                now = pos[top];
            }
        }
        for(int i=1; i<=top; i++) putchar(ans[i]); puts("");
    }

}ac;

char str[max_len];
char tmp[max_len];

int main(void){__stTIME();__IOPUT();

    scs(str);

    int len = strlen(str);

    int n;

    sci(n);

    ac.init();

    for(int i=0; i<n; i++){
        scs(tmp);
        ac.insert(tmp, strlen(tmp));
    }

    ac.build();

    ac.query(str);



__enTIME();return 0;}


void __stTIME()
{
    #if _TIME
        START = clock();
    #endif
}

void __enTIME()
{
    #if _TIME
        END = clock();
        cerr<<"execute time = "<<(double)(END-START)/CLOCKS_PER_SEC<<endl;
    #endif
}

void __IOPUT()
{
    #if _INPUT
        freopen("in.txt", "r", stdin);
    #endif
    #if _OUTPUT
        freopen("out.txt", "w", stdout);
    #endif
}