【BZOJ4736】温暖会指引我们前行（Link-Cut Tree）

题面

题解

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<set>
#include<map>
#include<vector>
#include<queue>
using namespace std;
#define MAX 700000
#define lson (t[x].ch[0])
#define rson (t[x].ch[1])
#define rg register
inline int read()
{
rg int x=0,t=1;rg char ch=getchar();
while((ch<'0'||ch>'9')&&ch!='-')ch=getchar();
if(ch=='-')t=-1,ch=getchar();
while(ch<='9'&&ch>='0')x=x*10+ch-48,ch=getchar();
return x*t;
}
struct Node
{
int ch[2],ff;
int rev;
int sum,ma,v,r;
}t[MAX];
int S[MAX],top,n,m;
void pushup(int x)
{
t[x].sum=t[lson].sum+t[rson].sum+t[x].v;
t[x].ma=(t[t[lson].ma].r>t[t[rson].ma].r)?t[rson].ma:t[lson].ma;
if(t[x].r<t[t[x].ma].r)t[x].ma=x;
}
inline bool isroot(int x){return t[t[x].ff].ch[0]!=x&&t[t[x].ff].ch[1]!=x;}
inline void rotate(int x)
{
rg int y=t[x].ff,z=t[y].ff;
rg int k=t[y].ch[1]==x;
if(!isroot(y))t[z].ch[t[z].ch[1]==y]=x;t[x].ff=z;
t[y].ch[k]=t[x].ch[k^1];t[t[x].ch[k^1]].ff=y;
t[x].ch[k^1]=y;t[y].ff=x;
pushup(y);pushup(x);
}
inline void pushdown(int x)
{
if(!t[x].rev)return;
t[lson].rev^=1;t[rson].rev^=1;
t[x].rev^=1;
swap(lson,rson);
}
void Splay(int x)
{
S[top=1]=x;
for(int i=x;!isroot(i);i=t[i].ff)S[++top]=t[i].ff;
while(top)pushdown(S[top--]);
while(!isroot(x))
{
int y=t[x].ff,z=t[y].ff;
if(!isroot(y))
(t[y].ch[1]==x)^(t[z].ch[1]==y)?rotate(x):rotate(y);
rotate(x);
}
}
void access(int x){for(int y=0;x;y=x,x=t[x].ff)Splay(x),t[x].ch[1]=y,pushup(x);}
void makeroot(int x){access(x);Splay(x);t[x].rev^=1;}
void split(int x,int y){makeroot(x);access(y);Splay(y);}
void link(int x,int y){makeroot(x);t[x].ff=y;}
void cut(int x,int y){split(x,y);t[x].ff=t[y].ch[0]=0;pushup(y);}
int findroot(int x){access(x);Splay(x);while(lson)x=lson;return x;}
int main()
{
n=read();m=read();
for(rg int i=0;i<=n;++i)t[i].r=1e9;
rg char ch[10];
while(m--)
{
scanf("%s",ch);
if(ch[0]=='f')
{
rg int id=read()+1,u=read()+1,v=read()+1,tmp=read(),len=read();
t[id+n].r=tmp;t[id+n].v=len;
if(findroot(u)!=findroot(v))link(u,id+n),link(v,id+n);//未联通
else
{
split(u,v);
if(t[t[v].ma].r<tmp)
{
rg int ss=t[v].ma;
cut(u,ss);cut(v,ss);
link(u,id+n);link(v,id+n);
}
}
}
else if(ch[0]=='m')
{
rg int u=read()+1,v=read()+1;
if(findroot(u)!=findroot(v))puts("-1");
else split(u,v),printf("%d\n",t[v].sum);
}
else
{
rg int id=read()+1,len=read();
makeroot(id+n);t[id+n].v=len;pushup(id+n);
}
}
return 0;
}