bzoj 4825: [Hnoi2017]单旋 [lct]

4825: [Hnoi2017]单旋

题意：有趣的spaly

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hnoi2017刚出来我就去做，当时这题作死用了ett，调了5节课没做出来然后发现好像直接用lct就行了然后弃掉了...

md用lct不知道好写到哪里去了1h就写完了

原树的父亲孩子可以直接维护

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <set>
using namespace std;
typedef long long ll;
#define lc t[x].ch[0]
#define rc t[x].ch[1]
#define pa t[x].fa
#define fir first
#define sec second
const int N = 4e5+5, INF=1e9+5;
inline int read() {
	char c=getchar(); int x=0,f=1;
	while(c<'0' || c>'9') {if(c=='-')f=-1; c=getchar();}
	while(c>='0' && c<='9') {x=x*10+c-'0'; c=getchar();}
	return x*f;
}

namespace lct {
	struct meow{int ch[2], fa, rev, size;} t[N];
	inline int wh(int x) {return t[pa].ch[1] == x;}
	inline int isr(int x) {return t[pa].ch[0] != x && t[pa].ch[1] != x;}
	inline void update(int x) {t[x].size = t[lc].size + t[rc].size + 1;}
	inline void rever(int x) {swap(lc, rc); t[x].rev ^= 1;}
	inline void pushdn(int x) {
		if(t[x].rev) {
			if(lc) rever(lc);
			if(rc) rever(rc);
			t[x].rev = 0;
		}
	}
	void pd(int x) {if(!isr(x)) pd(pa); pushdn(x);}
	inline void rotate(int x) {
		int f = t[x].fa, g = t[f].fa, c = wh(x);
		if(!isr(f)) t[g].ch[wh(f)] = x; t[x].fa = g;
		t[f].ch[c] = t[x].ch[c^1]; t[t[f].ch[c]].fa = f;
		t[x].ch[c^1] = f; t[f].fa = x;
		update(f); update(x);
	}
	void splay(int x) {
		pd(x);
		for(; !isr(x); rotate(x))
			if(!isr(pa)) rotate(wh(x) == wh(pa) ? pa : x);
	}
	void access(int x) {
		for(int y=0; x; y=x, x=pa) splay(x), rc=y, update(x);
	}
	void maker(int x) {
		access(x); splay(x); rever(x);
	}
	void link(int x, int y) { if(!x || !y) return;
		maker(x); t[x].fa = y;
	}
	void cut(int x, int y) { if(!x || !y) return;
		maker(x); access(y); splay(y); 
		t[x].fa = t[y].ch[0] = 0; update(y);
	}
	int que(int x, int y) {
		maker(x); access(y); splay(y);
		return t[y].size;
	}
} using lct::link; using lct::cut; using lct::que;

int root;
struct info {int fa, l, r;} t[N];

set< pair<int, int> > S;
set< pair<int, int> >::iterator i1, i2;
int tot;
void insert(int k) {
	++tot;
	i1 = i2 = S.insert(make_pair(k, tot)).fir;
	int a = 0, b = 0, x = tot;
	if(i1 != S.begin()) a = (--i1)->sec;
	if(++i2 != S.end()) b = i2->sec;
	if(!a && !b) root = x;
	else if(a && t[a].r == 0) t[a].r = x, t[x].fa = a, link(a, x);
	else if(b && t[b].l == 0) t[b].l = x, t[x].fa = b, link(b, x);
	printf("%d\n", que(root, x));
}

void spa_min() {
	int x = S.begin()->sec, r = t[x].r, p = t[x].fa; 
	printf("%d\n", que(root, x));
	if(x == root) return;

	cut(x, p); cut(x, r); link(p, r); link(x, root);
	t[x].r = root; t[root].fa = x; t[r].fa = p; t[p].l = r;
	root = x;
}

void spa_max() {
	i1 = S.end(); 
	int x = (--i1)->sec, l = t[x].l, p = t[x].fa;
	printf("%d\n", que(root, x));
	if(x == root) return;

	cut(x, p); cut(x, l); link(p, l); link(x, root);
	t[x].l = root; t[root].fa = x; t[l].fa = p; t[p].r = l;
	root = x;
}

void del_min() {
	i1 = S.begin();
	int x = S.begin()->sec, r = t[x].r, p = t[x].fa; //printf("\ndel_min %d  %d  %d\n", x, r, p);
	printf("%d\n", que(root, x));
	if(x == root) {
		cut(x, r); t[r].fa = 0; root = r;
	} else {
		cut(x, p); cut(x, r); link(p, r); 
		t[r].fa = p; t[p].l = r;
	}
	S.erase(i1);
}

void del_max() {
	i1 = S.end();  
	int x = (--i1)->sec, l = t[x].l, p = t[x].fa;
	printf("%d\n", que(root, x));
	if(x == root) {
		cut(x, l); t[l].fa = 0; root = l;
	} else {
		cut(x, p); cut(x, l); link(p, l); 
		t[l].fa = p; t[p].r = l;
	}
	S.erase(i1);
}

int m, type, k;
int main() {
	freopen("in", "r", stdin);
	m = read();
	for(int i=1; i<=m; i++) {
		type=read(); //printf("hi %d  %d\n", i, type);
		if(type == 1) k = read(), insert(k);
		if(type == 2) spa_min();
		if(type == 3) spa_max();
		if(type == 4) del_min();
		if(type == 5) del_max();
	}
}