[cogs2701]动态树

题面戳我

sol

比较裸啊。

注意操作顺序就行了。

code

#include<cstdio>
#include<algorithm>
using namespace std;
const int N = 200005;
int gi()
{
	int x=0,w=1;char ch=getchar();
	while ((ch<'0'||ch>'9')&&ch!='-') ch=getchar();
	if (ch=='-') w=0,ch=getchar();
	while (ch>='0'&&ch<='9') x=(x<<3)+(x<<1)+ch-'0',ch=getchar();
	return w?x:-x;
}
int n,q,fa[N],ls[N],rs[N],rev[N],sz[N],sum[N],Stack[N],top;
char s[1000];
bool isroot(int x){return ls[fa[x]]!=x&&rs[fa[x]]!=x;}
void pushup(int x){sum[x]=sum[ls[x]]+sum[rs[x]]+1+sz[x];}
void reverse(int x){swap(ls[x],rs[x]);rev[x]^=1;}
void pushdown(int x){if(!rev[x])return;if(ls[x])reverse(ls[x]);if(rs[x])reverse(rs[x]);rev[x]=0;}
void R_rotate(int x)
{
	int y=fa[x],z=fa[y];
	ls[y]=rs[x];
	if (rs[x]) fa[rs[x]]=y;
	fa[x]=z;
	if (y==ls[z]) ls[z]=x;if (y==rs[z]) rs[z]=x;
	rs[x]=y;fa[y]=x;
	pushup(y);
}
void L_rotate(int x)
{
	int y=fa[x],z=fa[y];
	rs[y]=ls[x];
	if (ls[x]) fa[ls[x]]=y;
	fa[x]=z;
	if (y==ls[z]) ls[z]=x;if (y==rs[z]) rs[z]=x;
	ls[x]=y;fa[y]=x;
	pushup(y);
}
void splay(int x)
{
	Stack[top=1]=x;
	for (int i=x;!isroot(i);i=fa[i])
		Stack[++top]=fa[i];
	while (top) pushdown(Stack[top--]);
	while (!isroot(x))
	{
		int y=fa[x],z=fa[y];
		if (isroot(y))
			if (x==ls[y]) R_rotate(x);
			else L_rotate(x);
		else
			if (y==ls[z])
				if (x==ls[y]) R_rotate(y),R_rotate(x);
				else L_rotate(x),R_rotate(x);
			else
				if (x==ls[y]) R_rotate(x),L_rotate(x);
				else L_rotate(y),L_rotate(x);
	}
	pushup(x);
}
void access(int x){for (int y=0;x;y=x,x=fa[x]) splay(x),sz[x]+=sum[rs[x]]-sum[y],rs[x]=y,pushup(x);}
void makeroot(int x){access(x);splay(x);reverse(x);}
int findroot(int x){access(x);splay(x);while (ls[x]) x=ls[x];return x;}
void link(int x,int y){makeroot(x);makeroot(y);fa[x]=y;sz[y]+=sum[x];pushup(y);}
int main()
{
	//freopen("dynamic_tree.in","r",stdin);
	//freopen("dynamic_tree.out","w",stdout);
	n=gi();q=gi();
	for (int i=1;i<=n;i++) sum[i]=1;
	while (q--)
	{
		int opt=gi(),u=gi();
		if (opt==1) makeroot(u);
		if (opt==2) access(u),printf("%d\n",sz[u]+1);
		if (opt==3) {int v=gi(),rt=findroot(u);link(u,v);makeroot(rt);}
	}
	return 0;
}