bzoj1180 tree

题目链接

link cut tree

模板题

link cut tree不都是模板题嘛？(雾

 #include<algorithm>
 #include<iostream>
 #include<cstdlib>
 #include<cstring>
 #include<cstdio>
 #include<string>
 #include<cmath>
 #include<ctime>
 #include<queue>
 #include<stack>
 #include<map>
 #include<set>
 #define rre(i,r,l) for(int i=(r);i>=(l);i--)
 #define re(i,l,r) for(int i=(l);i<=(r);i++)
 #define Clear(a,b) memset(a,b,sizeof(a))
 #define inout(x) printf("%d",(x))
 #define douin(x) scanf("%lf",&x)
 #define strin(x) scanf("%s",(x))
 #define LLin(x) scanf("%lld",&x)
 #define op operator
 #define CSC main
 typedef unsigned long long ULL;
 typedef const int cint;
 typedef long long LL;
 using namespace std;
 void inin(int &ret)
 {
     ret=;int f=;char ch=getchar();
     while(ch<''||ch>''){if(ch=='-')f=;ch=getchar();}
     while(ch>=''&&ch<='')ret*=,ret+=ch-'',ch=getchar();
     ret=f?-ret:ret;
 }
 int n,q,w[],ch[][],fa[],sum[],rev[];
 bool isroot(int x){return ch[fa[x]][]!=x&&ch[fa[x]][]!=x;}
 void maintain(int x){if(x)sum[x]=w[x]+sum[ch[x][]]+sum[ch[x][]];}
 void rotate(int x)
 {
     int y=fa[x],z=fa[y];
     if(!isroot(y))ch[z][ch[z][]==y]=x;
     fa[x]=z,fa[y]=x;
     int d=ch[y][]==x;
     fa[ch[x][d^]]=y;
     ch[y][d]=ch[x][d^];
     ch[x][d^]=y;
     maintain(y);maintain(x);
 }
 void down(int x)
 {
     if(rev[x])
     {
         swap(ch[x][],ch[x][]);
         rev[ch[x][]]^=;
         rev[ch[x][]]^=;
         rev[x]=;
     }
 }
 int sta[],top;
 void splay(int x)
 {
     top=;int xx=x;sta[++top]=xx;
     while(!isroot(xx))sta[++top]=fa[xx],xx=fa[xx];
     while(top)down(sta[top--]);
     while(!isroot(x))
     {
         int y=fa[x],z=fa[y];
         if(!isroot(y))
             if((ch[y][]==x)^(ch[z][]==y))rotate(x);
             else rotate(y);else ;
         rotate(x);
     }
 }
 void access(int x)
 {
     int temp=;
     while(x)
     {
         splay(x);
         ch[x][]=temp;maintain(x);
         temp=x,x=fa[x];
     }
 }
 void reverse(int x)
 {
     access(x),splay(x),rev[x]^=;
 }
 void link(int x,int y)
 {
     reverse(x),fa[x]=y;
 }
 void cut(int x,int y)
 {
     reverse(x),access(y),fa[x]=ch[y][]=;maintain(y);
 }
 int find(int x)
 {
     access(x);splay(x);
     while(ch[x][])x=ch[x][];
     return x;
 }
 int main()
 {
     inin(n);char ss[];
     re(i,,n)inin(w[i]),sum[i]=w[i];
     inin(q);
     re(i,,q)
     {
         strin(ss);int a,b;inin(a),inin(b);
         if(ss[]=='b')
         {
             if(find(a)==find(b))cout<<"no\n";
             else
             {
                 cout<<"yes\n";
                 link(a,b);
             }
         }
         else if(ss[]=='p')
         {
             splay(a),w[a]=b,maintain(a);
         }
         else if(ss[]=='e')
         {
             if(find(a)!=find(b)){cout<<"impossible\n";continue;}
             reverse(a),access(b),splay(b);
             printf("%d\n",sum[b]);
         }
     }
      return ;
 }