LCT维护连通性。
#include <cstdio> #include <cstring> #include <cstdlib> #include <iostream> #include <algorithm> using namespace std; const int MAXN=10000+2; typedef struct NODE{ NODE *child[2],*f; bool rev; } *TREE; TREE root,Null,mark[MAXN]; int N,M; char s[10]; TREE NewNode(TREE f){ TREE x=new NODE; x->f=f,x->child[0]=x->child[1]=Null; x->rev=0; return x; } void Initialize(int N){ Null=NewNode(0); for(int i=1;i<=N;i++) mark[i]=NewNode(Null); } void Pushdown(TREE &x){ if(x->f->child[0]==x || x->f->child[1]==x) Pushdown(x->f); if(x->rev){ swap(x->child[0],x->child[1]); x->child[0]->rev^=1,x->child[1]->rev^=1; x->rev=0; } } void Rotate(TREE &x,bool t){ TREE y=x->f; y->child[!t]=x->child[t],x->child[t]->f=y,x->f=y->f; if(y->f->child[0]==y) y->f->child[0]=x; if(y->f->child[1]==y) y->f->child[1]=x; x->child[t]=y,y->f=x; } void Splay(TREE &x){ Pushdown(x); TREE y=x->f; while(y->child[0]==x || y->child[1]==x){ if(y->child[0]==x){ if(y->f->child[0]==y) Rotate(y,1); Rotate(x,1); } else{ if(y->f->child[1]==y) Rotate(y,0); Rotate(x,0); } y=x->f; } } void Access(TREE &x){ TREE y=Null,z=x; while(z!=Null){ Splay(z); z->child[1]=y; y=z,z=z->f; } } void Move(TREE &x){ Access(x),Splay(x); x->rev^=1,Pushdown(x); } void Link(TREE &x,TREE &y){ Move(x); x->child[0]=Null,x->f=y; } void Cut(TREE &x,TREE &y){ Move(x); x->child[1]=Null; Access(y); x->child[1]=Null; Splay(y); y->f=Null; } TREE Query(TREE &x){ TREE y=x; while(y->f!=Null) y=y->f; return y; } int main(){ scanf("%d %d",&N,&M); Initialize(N); for(int i=1,x,y;i<=M;i++){ scanf("%s %d %d",s,&x,&y); if(s[0]=='Q') if(Query(mark[x])==Query(mark[y])) puts("Yes"); else puts("No"); if(s[0]=='C') Link(mark[x],mark[y]); if(s[0]=='D') Cut(mark[x],mark[y]); } return 0; }