[SDOI2008]洞穴勘测

Posted 2020-10-31 殇雪

SOL： LCT维护联通性，当然，启发式合并并查集可能会更好写。

   

#include<bits/stdc++.h>
#define N 200007
int rev[N],ch[N][2],f[N],q[N],top;
using namespace std;
inline void push_down(int x) {
    if (rev[x]) {
        rev[ch[x][0]]^=1; rev[ch[x][1]]^=1; rev[x]=0;
        swap(ch[x][0],ch[x][1]);
    }
}
inline bool rt(int x){
    return ch[f[x]][0]!=x&&ch[f[x]][1]!=x;
}
inline void ro(int x){
    int y=f[x],z=f[y],kind=(ch[y][0]==x);
    if (!rt(y)) ch[z][ch[z][1]==y]=x;
    f[ch[x][kind]]=y; f[y]=x; f[x]=z;
    ch[y][kind^1]=ch[x][kind]; ch[x][kind]=y;
}
//inline void splay(int x){
inline void splay(int x) {
    q[top=1]=x;
    for (int i=x;!rt(i);i=f[i]) q[++top]=f[i];
    while (top) push_down(q[top--]);
    while (!rt(x)) {
        int y=f[x],z=f[y];
        if (!rt(y)) 
        {
           if (ch[y][0]==x^ch[z][0]==y) ro(x); 
           else ro(y);
        }
        ro(x);
    }
//    push_up(x);
}
inline void access(int x) {
    for (int t=0;x;t=x,x=f[x]) splay(x),ch[x][1]=t;
}
inline void make_rt(int x) {
    access(x); splay(x); rev[x]^=1;
}
inline void link(int x,int y){
    make_rt(x); f[x]=y;
}
inline int find(int x){
    access(x); splay(x); while (ch[x][0]) push_down(x),x=ch[x][0];
    return x;
}
inline void cut(int x,int y){
    make_rt(x); 
    if (find(y)==x&&f[x]==y&&!ch[x][1])  f[x]=ch[y][0]=0;
}
int n,m,x,y;
char as[19];
signed main () {
//    freopen("a.in","r",stdin);
    scanf("%d%d",&n,&m);
    while (m--) {
        scanf("%s",as);
        scanf("%d%d",&x,&y);
        if (as[0]==‘Q‘) {
            printf("%s\n",(find(x)^find(y))?"No":"Yes");
        } else if (as[0]==‘C‘) {
            if (find(x)^find(y)) 
             link(x,y);
        } else {
            if (find(x)==find(y)) cut(x,y);
        }
    }
}