Ural1553.Caves and Tunnels

水题一道……动态维护树链上的最大点权，动态树水过……

wa了几次……因为没看清楚题……点权的修改是在原来的点权基础之上的……

点数过多，不能用DFS建图

//Lib#include<cstdio>#include<cstring>#include<cstdlib>#include<cmath>#include<ctime>#include<iostream>#include<algorithm>#include<vector>#include<string>#include<queue>using namespace std;//Macro#define rep(i,a,b) for(int i=a,tt=b;i<=tt;++i)#define rrep(i,a,b) for(int i=a,tt=b;i>=tt;--i)#define erep(i,e,x) for(int i=x;i;i=e[i].next)#define irep(i,x) for(__typedef(x.begin()) i=x.begin();i!=x.end();i++)#define read() (strtol(ipos,&ipos,10))#define sqr(x) ((x)*(x))#define pb push_back#define PS system("pause");typedef long long ll;typedef pair<int,int> pii;const int oo=100000000;const double inf=1e20;const double eps=1e-6;string name="",in=".in",out=".out";//Varstruct T{int LC,RC,FA,KEY,MAX;#define lc(x) tree[x].LC#define rc(x) tree[x].RC#define fa(x) tree[x].FA#define key(x) tree[x].KEY#define Max(x) tree[x].MAX}tree[100008];struct E{int next,node;}e[200008];queue<int> q;int n,Q,tot,h[100008];bool vis[100008];bool isRoot(int x){return lc(fa(x))!=x&&rc(fa(x))!=x;}inline void Update(int x){Max(x)=max(key(x),max(Max(lc(x)),Max(rc(x))));}void Zig(int x){int y=fa(x),z=fa(y);if(lc(z)==y)lc(z)=x;else if(rc(z)==y)rc(z)=x;fa(x)=z;fa(rc(x))=y;lc(y)=rc(x);fa(y)=x;rc(x)=y;Update(y);}void Zag(int x){int y=fa(x),z=fa(y);if(lc(z)==y)lc(z)=x;else if(rc(z)==y)rc(z)=x;fa(x)=z;fa(lc(x))=y;rc(y)=lc(x);fa(y)=x;lc(x)=y;Update(y);}void Splay(int x){for(int y,z;!isRoot(x);){y=fa(x);z=fa(y);if(isRoot(y))if(lc(y)==x)Zig(x);else Zag(x);elseif(lc(z)==y)if(lc(y)==x)Zig(y),Zig(x);else Zag(x),Zig(x);elseif(rc(y)==x)Zag(y),Zag(x);else Zig(x),Zag(x);}}void Expose(int x){for(int y=0;x;x=fa(x)){Splay(x);rc(x)=y;Update(x);y=x;}}void Build(){q.push(1);vis[1]=true;int x,y;while(!q.empty()){x=q.front();q.pop();erep(i,e,h[x]){y=e[i].node;if(vis[y])continue;q.push(y);vis[y]=true;fa(y)=x;}}}void add(int a,int b){e[++tot].next=h[a];e[tot].node=b;h[a]=tot;}void Init(){int a,b;scanf("%d",&n);rep(i,1,n-1)scanf("%d%d",&a,&b),add(a,b),add(b,a);Build();}void Change(int x,int y){key(x)+=y;Splay(x);}int Query(int x,int y){Expose(y);for(y=0;x;x=fa(x)){Splay(x);if(!fa(x))return max(Max(rc(x)),max(Max(y),key(x)));rc(x)=y;Update(x);y=x;}}void Work(){char ch[10];int a,b;key(0)=Max(0)=-oo;scanf("%d",&Q);rep(i,1,Q){scanf("%s%d%d",ch,&a,&b);if(ch[0]=='I')Change(a,b);else printf("%d\n",Query(a,b));}}int main(){//freopen((name+in).c_str(),"r",stdin);//freopen((name+out).c_str(),"w",stdout);Init();Work();return 0;}