URAL1553 Caves and Tunnels

LCT模板题

代码

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#include<iostream>
#define L(i) (T[i].s[0])
#define R(i) (T[i].s[1])
#define F(i) (T[i].fa)
#define Loc(i) (R(F(i))==i)
#define For(i,j,k) for(register int i=(j);i<=(int)k;i++)
#define Forr(i,j,k) for(register int i=(j);i>=(int)k;i--)
#define Set(a,b) memset(a,b,sizeof(a))
using namespace std;
const int N=200010;
int Begin[N],to[N*2],Next[N*2],e,n,m;
inline void add(int x,int y){
    to[++e]=y;Next[e]=Begin[x];Begin[x]=e;
}
inline void read(int &x){
    x=0;char c=getchar();int f=(c=='-');
    while(c<'0'||c>'9')c=getchar(),f|=(c=='-');
    while(c>='0'&&c<='9')x=x*10+c-'0',c=getchar();
    if(f)x=-x;
}
struct node{
    int s[2],fa,rev,v,mx;
};
struct LCT{
    node T[N];
    inline void pushup(int x){
        T[x].mx=max(max(T[L(x)].mx,T[R(x)].mx),T[x].v);
    }
    inline void pushdown(int x){
        if(T[x].rev){
            T[x].rev^=1,T[L(x)].rev^=1,T[R(x)].rev^=1;
            swap(L(x),R(x));
        }
    }
    inline bool isrt(int x){
        return R(F(x))!=x&&L(F(x))!=x;
    }
    void Pushdown(int x){
        if(!isrt(x))Pushdown(F(x));
        pushdown(x);
    }
    inline void Rotate(int x){
        int A=F(x),B=F(A),l=Loc(x),r=l^1,d=Loc(A);
        if(!isrt(A))T[B].s[d]=x;F(x)=B;
        F(A)=x,F(T[x].s[r])=A,T[A].s[l]=T[x].s[r],T[x].s[r]=A;
        pushup(A),pushup(x);
    }
    inline void splay(int x){
        Pushdown(x);
        while(!isrt(x)){
            if(!isrt(F(x)))Rotate(x);
            Rotate(x);
        }
    }
    inline void access(int x){
        for(int i=0;x;i=x,x=F(x))
            splay(x),R(x)=i,pushup(x);
    }
    inline void reverse(int x){
        access(x),splay(x),T[x].rev^=1;
    }
    inline void modify(int x,int v){
        access(x),splay(x),T[x].v+=v,pushup(x);
    }
    inline int query(int x,int y){
        reverse(x),access(y),splay(y);
        return T[y].mx;
    }
    inline void clear(){
        Set(T,0);
    }
}t;
void dfs(int u,int fa){
    for(int i=Begin[u];i;i=Next[i]){
        int v=to[i];
        if(v==fa)continue;
        t.T[v].fa=u;
        dfs(v,u);
    }
}
char st[10];
int main(){
    int u,v;
    while(scanf("%d",&n)!=EOF){
        Set(Begin,0),e=0;t.clear();
        For(i,1,n-1){
            read(u),read(v);
            add(u,v),add(v,u);
        }
        dfs(1,0);
        read(m);
        while(m--){
            scanf("%s",st);
            read(u),read(v);
            if(st[0]=='I')t.modify(u,v);
            else printf("%d\n",t.query(u,v));
        }
    }
}