[BZOJ2843][LCT]极地旅行社

来源：互联网发布：将压缩的js还原编辑：程序博客网时间：2024/04/27 20:24
LCT裸题
#include <cstdio>#include <algorithm>#include <iostream>#define N 30010using namespace std;int n,m,tp,x,y;int A[N],fa[N],ch[N][2],v[N],rev[N],sta[N];char op[10];inline int isl(int x){return ch[fa[x]][1]==x;}inline int isr(int x){return ch[fa[x]][0]!=x&&ch[fa[x]][1]!=x;}inline void pushdown(int x){  if(!(x&&rev[x])) return;  swap(ch[x][0],ch[x][1]);  if(ch[x][0]) rev[ch[x][0]]^=1;  if(ch[x][1]) rev[ch[x][1]]^=1;  rev[x]=0;}inline void upd(int x){  if(!x) return;  v[x]=A[x];  if(ch[x][0]) v[x]+=v[ch[x][0]];  if(ch[x][1]) v[x]+=v[ch[x][1]];}inline void rot(int x){  int y=fa[x],z=fa[y],lor=isl(x);  if(!isr(y)) ch[z][ch[z][1]==y]=x; fa[x]=z;  if(ch[y][lor]=ch[x][lor^1]) fa[ch[y][lor]]=y;  fa[ch[x][lor^1]=y]=x; upd(y); upd(x);}inline void splay(int x){  sta[tp=1]=x;  for(int i=x;!isr(i);i=fa[i]) sta[++tp]=fa[i];  for(;tp;--tp) pushdown(sta[tp]);  for(;!isr(x);rot(x))    if(!isr(fa[x])) rot(isl(x)^isl(fa[x])?x:fa[x]);}inline void access(int x){  int t=0;  for(;x;x=fa[x]) splay(x),ch[x][1]=t,t=x,upd(x);}inline void reverse(int x){access(x);splay(x);rev[x]^=1;}inline void link(int x,int y){reverse(x);fa[x]=y;access(x);}inline void cut(int x,int y){reverse(x);access(y);splay(y);ch[y][0]=fa[x]=0;}inline int fifa(int x){  access(x);splay(x);  while(ch[x][0]) x=ch[x][0];  return x;}inline void reaD(int &x){  char Ch=getchar();x=0;  for(;Ch>'9'||Ch<'0';Ch=getchar());  for(;Ch>='0'&&Ch<='9';x=x*10+Ch-'0',Ch=getchar());}int main(){  freopen("1.in","r",stdin);  freopen("1.out","w",stdout);  reaD(n);  for(int i=1;i<=n;i++) reaD(A[i]);  reaD(m);  while(m--){    scanf("%s",op);    if(op[0]=='b'){      reaD(x);reaD(y);      if(fifa(x)==fifa(y)){puts("no");continue;}      link(x,y); puts("yes");    }    else if(op[0]=='e'){      reaD(x);reaD(y);      if(fifa(x)!=fifa(y)){puts("impossible");continue;}      reverse(x); access(y); splay(y);      printf("%d\n",v[y]-v[ch[y][1]]);    }    else{      reaD(x);reaD(y);      access(x); splay(x);      A[x]=y; upd(x);    }  }}
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