【BZOJ 1180】[CROATIAN2009]OTOCI LCT

来源：互联网发布：兰州ps软件班编辑：程序博客网时间：2024/05/18 02:53

第一次只用30分钟写完然后1A有点激动，虽然是一道很裸很傻逼的LCT啦

#include<cstdio>#include<cstring>#include<iostream>#define ls(u) ch[u][0]#define rs(u) ch[u][1]#define maxn 300021using namespace std;int n,m,ch[maxn][2],sum[maxn],q[maxn],flag[maxn],top,fa[maxn],val[maxn];inline int Q(int u){return u==rs(fa[u]);}inline int isrt(int u){return !fa[u]||(u!=ls(fa[u])&&u!=rs(fa[u]));}inline void push_up(int u){sum[u]=sum[ls(u)]+sum[rs(u)]+val[u];}inline void push_down(int u){swap(ls(u),rs(u));flag[u]=0;if(ls(u))flag[ls(u)]^=1;if(rs(u))flag[rs(u)]^=1;}void rotate(int u){int d=!Q(u),f=fa[u];if(!isrt(f))ch[fa[f]][Q(f)]=u;fa[u]=fa[f];if(ch[u][d])fa[ch[u][d]]=f;ch[f][!d]=ch[u][d];fa[f]=u;ch[u][d]=f;push_up(f);push_up(u);}void splay(int u){q[top=1]=u;for(int i=u;!isrt(i);i=fa[i])q[++top]=fa[i];for(int i=top;i>=1;i--)if(flag[q[i]])push_down(q[i]);while(!isrt(u)){if(isrt(fa[u]))rotate(u);else {if(Q(u)==Q(fa[u]))rotate(fa[u]);else rotate(u);rotate(u);}}}void access(int u){for(int x=0;u;u=fa[x=u]){splay(u);rs(u)=x;push_up(u);}}void makert(int u){access(u);splay(u);flag[u]^=1;}void link(int a,int b){makert(a);fa[a]=b;}bool isuni(int a,int b){makert(a);access(b);splay(b);while(ls(b))b=ls(b);return b==a;}void update(int u,int x){access(u);splay(u);val[u]=x;push_up(u);}void query(int a,int b){if(!isuni(a,b))puts("impossible");else printf("%d\n",sum[b]);}int main(){scanf("%d",&n);for(int i=1;i<=n;i++)scanf("%d",val+i);scanf("%d",&m);int a,b;char s[15];while(m--){scanf("%s%d%d",s,&a,&b);if(s[0]=='b'){if(!isuni(a,b))link(a,b),puts("yes");else puts("no");}else if(s[0]=='p'){update(a,b);}else query(a,b);}return 0;}

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