cogs1889 [SDOI2008]Cave 洞穴勘测 link-cut tree

link-cut tree

// It is made by XZZ
#include<cstdio>
#include<algorithm>
#define il inline
#define rg register
#define vd void
#define sta static
typedef long long ll;
il int gi(){
    rg int x=0,f=1;rg char ch=getchar();
    while(ch<'0'||ch>'9')f=ch=='-'?-1:f,ch=getchar();
    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
    return x*f;
}
const int maxn=10001;
namespace LCT{
	int ch[maxn][2],fa[maxn];bool rev[maxn];
	il vd down(int x){if(rev[x])rev[x]=0,rev[ch[x][0]]^=1,rev[ch[x][1]]^=1,std::swap(ch[x][0],ch[x][1]);}
	il bool isrt(int x){return ch[fa[x]][0]!=x&&ch[fa[x]][1]!=x;}
	il vd rot(int x){
		sta int y,z,o;
		y=fa[x],z=fa[y],o=x==ch[y][1];
		if(!isrt(y))ch[z][y==ch[z][1]]=x;fa[x]=z;
		ch[y][o]=ch[x][!o];fa[ch[x][!o]]=y;
		ch[x][!o]=y;fa[y]=x;
	}
	il vd splay(int x){
		sta int stk[maxn],top;stk[top=1]=x;
		for(rg int i=x;!isrt(i);i=fa[i])stk[++top]=fa[i];
		while(top)down(stk[top--]);
		for(rg int y=fa[x],z=fa[y];!isrt(x);rot(x),y=fa[x],z=fa[y])
			if(!isrt(y))rot(((x==ch[y][1])^(y==ch[z][1]))?y:x);
	}
	il vd access(int x){for(rg int y=0;x;x=fa[y=x])splay(x),ch[x][1]=y;}
	il vd makert(int x){access(x),splay(x);rev[x]^=1;}
	il int find(int x){for(access(x),splay(x);ch[x][0];x=ch[x][0]);return x;}
	il vd link(int x,int y){makert(x),fa[x]=y;}
	il vd cut(int x,int y){makert(x);access(y),splay(y);fa[x]=ch[y][0]=0;}
}
int main(){
 	freopen("sdoi2008_cave.in","r",stdin);
 	freopen("sdoi2008_cave.out","w",stdout);
	using namespace LCT;
	int n,m,u,v;char opt[20],str[][5]={"No","Yes"};
	n=gi(),m=gi();
	while(m--){
		scanf("%s",opt);u=gi(),v=gi();
		if(opt[0]=='Q')puts(str[find(u)==find(v)]);
		else if(opt[0]=='C')link(u,v);
		else cut(u,v);
	}
    return 0;
}

常数有点小大。