BZOJ 2049 [SDOI2008]洞穴勘测 (LCT)

题目大意：维护一个森林，支持边的断，连，以及查询连通性

LCT裸题 洛谷P2147传送门

1A了，给自己鼓鼓掌

 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #define il inline
 #define inf 500000
 #define N 10100
 using namespace std;

 int n,m,tp;
 int stk[N];
 struct LinkCutTree{
     int fa[N],ch[N][],rv[N];
     il int idf(int x){return ch[fa[x]][]==x?:;}
     il void con(int x,int ff,int p){fa[x]=ff,ch[ff][p]=x;}
     il int isroot(int x){return (ch[fa[x]][]!=x&&ch[fa[x]][]!=x)?:;}
     il void rev(int x){swap(ch[x][],ch[x][]),rv[x]^=;}
     il void pushdown(int x)
     {
         if(!rv[x]) return;
         if(ch[x][]) rev(ch[x][]);
         if(ch[x][]) rev(ch[x][]);
         rv[x]=;
     }
     il void rot(int x)
     {
         int y=fa[x];int ff=fa[y];int px=idf(x);int py=idf(y);
         if(!isroot(y)) ch[ff][py]=x;
         fa[x]=ff;con(ch[x][px^],y,px),con(y,x,px^);
         //pushup(y),pushup(x);
     }
     void splay(int x)
     {
         int y=x;stk[++tp]=x;
         while(!isroot(y)){stk[++tp]=fa[y],y=fa[y];}
         while(tp){pushdown(stk[tp--]);}
         while(!isroot(x))
         {
             y=fa[x];
             if(isroot(y)) rot(x);
             else if(idf(y)==idf(x)) rot(y),rot(x);
             else rot(x),rot(x);
         }
     }
     void access(int x){for(int y=;x;y=x,x=fa[x])splay(x),ch[x][]=y;/*pushup(x)*/}
     il void mkroot(int x){access(x),splay(x),rev(x);}
     il void split(int x,int y){mkroot(x),access(y),splay(y);}
     int findrt(int x){access(x),splay(x);while(ch[x][])pushdown(x),x=ch[x][];return x;}
     il void link(int x,int y){mkroot(x);if(findrt(y)!=x)fa[x]=y;}
     il void cut(int x,int y){mkroot(x);if(findrt(y)==x&&fa[x]==y&&!ch[x][])fa[x]=ch[y][]=;/*pushup(y)*/}
 }lct;
 int gint()
 {
     int rett=,fh=;char c=getchar();
     while(c<''||c>''){if(c=='-')fh=-;c=getchar();}
     while(c>=''&&c<=''){rett=(rett<<)+(rett<<)+c-'';c=getchar();}
     return rett*fh;
 }

 int main()
 {
     n=gint(),m=gint();
     int fl,x,y;char str[];
     for(int i=;i<=m;i++)
     {
         scanf("%s",str);
         x=gint(),y=gint();
         if(str[]=='C'){lct.link(x,y);}
         if(str[]=='D'){lct.cut(x,y);}
         if(str[]=='Q'){
             if(lct.findrt(x)==lct.findrt(y))
                 printf("Yes\n");
             else printf("No\n");}
     }
     return ;
 }