bzoj2555 substring(LCT 后缀自动机）

转载于 2019-03-28 13:55:00 发布 · 92 阅读

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/luoyibujue/p/10614515.html

本文介绍了一种使用LCT树维护动态集合大小的方法，并结合AC自动机实现了字符串匹配和查询功能。通过具体实现细节展示了如何高效地处理字符串查询和更新操作。

/*
动态求right集合的大小 
LCT维护parent树即可
注意 由于树是有向的不会换根并且每次操作单一， 于是不需要维护子树和（写起来很麻烦）
直接打标记修改即可 
*/

#include<cstdio>
#include<algorithm>
#include<iostream>
#include<cstring>
#include<queue>
#define ll long long 
#define M 1200010
#define mmp make_pair
using namespace std;
int read()
{
    int nm = 0, f = 1;
    char c = getchar();
    for(; !isdigit(c); c = getchar()) if(c == '-') f = -1;
    for(; isdigit(c); c = getchar()) nm = nm * 10 + c - '0';
    return nm * f;
}

int mask, ans;
struct Lct
{
    #define ls ch[x][0]
    #define rs ch[x][1]
    int ch[M][2], rev[M], ver[M], fa[M], s[M]; 
    bool isr(int x)
    {
        return ch[fa[x]][0] != x && ch[fa[x]][1] != x;
    }
    
    void up(int x, int vv)
    {
        ver[x] += vv;
        s[x] += vv;
    }

    void pushdown(int x)
    {
        if(s[x])
        {
            up(ls, s[x]);
            up(rs, s[x]);
            s[x] = 0; 
        }
    }
    
    void pd(int x)
    {
        if(!isr(x)) pd(fa[x]);
        pushdown(x); 
    }
    
    
    void rotate(int x)
    {
        int y = fa[x], q = fa[y];
        bool dy = (ch[y][1] == x), dz = (ch[q][1] == y);
        if(!isr(y)) ch[q][dz] = x;
        fa[x] = q;
        fa[ch[x][dy ^ 1]] = y;
        ch[y][dy] = ch[x][dy ^ 1];
        ch[x][dy ^ 1] = y;
        fa[y] = x;
    }
    
    void splay(int x)
    {
        pd(x);
        while(!isr(x))
        {
            int y = fa[x], q = fa[y];
            if(!isr(y))
            {
                if((ch[y][1] == x) ^ (ch[q][1] == y))
                {
                    rotate(x);
                }
                else rotate(y);
            }
            rotate(x);
        }
    }
    
    void access(int x)
    {
        for(int y = 0; x; y = x, x = fa[x]) splay(x), rs = y;
    }
        
    void link(int x, int y)
    {
        fa[x] = y;
        access(y);
        splay(y);
        up(y, ver[x]);
    }
    
    void cut(int x)
    {
        access(x), splay(x), up(ls, -ver[x]), fa[ls] = 0, ls = 0;
    }
}T;
    
int ch[M][26], len[M], fa[M], lst = 1, cnt = 1;

void insert(int c)
{
    int p = ++cnt, f = lst;
    lst = p;
    len[p] = len[f] + 1;
    T.ver[p] = 1;
    while(f && !ch[f][c]) ch[f][c] = p, f = fa[f];
    if(!f)
    {
        fa[p] = 1;
        T.link(p, 1);
    }
    else
    {
        int q = ch[f][c];
        if(len[q] == len[f] + 1)
        {
            T.link(p, q);
            fa[p] = q;
        }
        else
        {
            int nq = ++cnt;
            len[nq] = len[f] + 1;
            memcpy(ch[nq], ch[q], sizeof(ch[nq]));
            fa[nq] = fa[q];
            T.link(nq, fa[q]);
            fa[q] = fa[p] = nq;
            T.cut(q);
            T.link(q, nq);
            T.link(p, nq);
            while(f && ch[f][c] == q) ch[f][c] = nq, f = fa[f];
        }
    }
}

char s[M * 3];
void work()
{
    int mlgb = mask;
    int l = strlen(s);
    for(int i = 0; i < l; i++)
    {
        mlgb = (mlgb * 131 + i) % l;
        swap(s[i], s[mlgb]);
    }
//  puts(s); 
}
    
int main()
{
    int q = read();
    scanf("%s", s + 1);
    int l = strlen(s + 1);
    for(int i = 1; i <= l; i++) insert(s[i] - 'A');
    while(q--)
    {
        scanf("%s", s + 1);
        if(s[1] == 'Q')
        {
            scanf("%s", s);
            l = strlen(s);
            work();
            int now = 1;
            for(int i = 0; i < l; i++) now = ch[now][s[i] - 'A'];
            if(!now) ans = 0;
            else
            {
                T.splay(now);
                ans = T.ver[now];
            }
            cout << ans << "\n";
            mask ^= ans; 
        }
        else
        {
            scanf("%s", s);
            l = strlen(s);
            work();
            for(int i = 0; i < l; i++) insert(s[i] - 'A');
        }
    }
    return 0;
}
/*
2
BBABBBBAAB

ADD BBBAAB

QUERY BBA
*/

转载于:https://www.cnblogs.com/luoyibujue/p/10614515.html