P4312 [COCI 2009] OTOCI / 极地旅行社

题目

P4312 [COCI 2009] OTOCI / 极地旅行社

做法

添边，修改权值，查询链和，为什么有种莫名的熟悉感，水题啊！！！

十分钟打完后调了二十分钟才做完Rotate(x)犯了个**错误，宁可慢点打也要一遍过

My complete code

#include<cstdio>
#include<cstring>
#include<string>
#include<iostream>
#include<algorithm>
using namespace std;
typedef int LL;
const LL maxn=1e6;
inline LL Read(){
	LL x(0),f(1);char c=getchar();
	while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
	while(c>='0'&&c<='9')x=(x<<3)+(x<<1)+c-'0',c=getchar();
	return x*f;
}
LL n,m;
LL sum[maxn],son[maxn][2],fa[maxn],val[maxn],sta[maxn],r[maxn];
char s[100];
inline void Update(LL x){
	sum[x]=sum[son[x][0]]+sum[son[x][1]]+val[x];
}
inline bool Notroot(LL x){
	return son[fa[x]][0]==x||son[fa[x]][1]==x;
}
inline void Pushr(LL x){
	swap(son[x][0],son[x][1]),r[x]^=1;
}
inline void Pushdown(LL x){
	if(r[x]){
		if(son[x][0])Pushr(son[x][0]);
		if(son[x][1])Pushr(son[x][1]);
		r[x]=0;
	}
}
inline void Rotate(LL x){
	LL y(fa[x]),z(fa[y]),lz=(son[y][1]==x);
	if(Notroot(y)) son[z][son[z][1]==y]=x;fa[x]=z;
	son[y][lz]=son[x][lz^1];
	if(son[y][lz]) fa[son[y][lz]]=y;
	son[x][lz^1]=y; fa[y]=x;
	Update(y),Update(x);
}
inline void Splay(LL x){
	LL y(x),top(0); sta[++top]=y;
	while(Notroot(y)) sta[++top]=y=fa[y];
	while(top) Pushdown(sta[top--]);
	while(Notroot(x)){
		y=fa[x];
		if(Notroot(y)){
			LL z(fa[y]);
			if(((son[z][1]==y)^(son[y][1]==x))==0) Rotate(y);
			else Rotate(x);
		}Rotate(x);
	}
}
inline void Access(LL x){
	for(LL y=0;x;y=x,x=fa[x])
	    Splay(x),son[x][1]=y,Update(x);
}
inline void Makeroot(LL x){
	Access(x),Splay(x),Pushr(x);
}
inline void Split(LL x,LL y){
	Makeroot(x);
	Access(y);
	Splay(y);
}
inline void Link(LL x,LL y){
	Makeroot(x);fa[x]=y;
}
inline LL Findroot(LL x){
	Access(x);
	Splay(x);
	while(son[x][0]) x=son[x][0]; Splay(x);
	return x;
}
int main(){
	n=Read();
	for(LL i=1;i<=n;++i) sum[i]=val[i]=Read();
	m=Read();LL ret(0);
	while(m--){
		scanf(" %s",s);
		LL a(Read()),b(Read());
		if(s[0]=='b'){
			if(Findroot(a)!=Findroot(b)){
				printf("yes\n");
				Link(a,b);
			}else printf("no\n");
		}else if(s[0]=='p'){
			Makeroot(a);
			val[a]=b;
			Update(a);
		}else if(s[0]=='e'){
			if(Findroot(a)!=Findroot(b))
			    printf("impossible\n");
			else{
                Split(a,b);
			    printf("%d\n",sum[b]);
			}
		}
	}return 0;
}