bzoj2816 [ZJOI2012]网络

Description

http://www.lydsy.com/JudgeOnline/upload/zjoi2012.pdf

正解：$link-cut \ tree$。

$LCT$板子题，直接维护$10$个$LCT$就行了。

注意修改颜色操作，修改后的颜色可能与之前颜色相同。

 #include <bits/stdc++.h>
 #define il inline
 #define RG register
 #define ll long long
 #define N (10005)

 using namespace std;

 map<int,int> mp[N];

 int d[N][],val[N],n,m,c,Q;

 il int gi(){
   RG int x=,q=; RG char ch=getchar();
   while ((ch<'' || ch>'') && ch!='-') ch=getchar();
   if (ch=='-') q=-,ch=getchar();
   while (ch>='' && ch<='') x=x*+ch-,ch=getchar();
   return q*x;
 }

 struct Link_Cut_Tree{

   int ch[N][],fa[N],sum[N],rev[N],st[N];

   il int isroot(RG int x){
     return ch[fa[x]][]!=x && ch[fa[x]][]!=x;
   }

   il void pushup(RG int x){
     sum[x]=max(val[x],max(sum[ch[x][]],sum[ch[x][]])); return;
   }

   il void pushdown(RG int x){
     rev[ch[x][]]^=,rev[ch[x][]]^=;
     swap(ch[x][],ch[x][]),rev[x]=; return;
   }

   il void rotate(RG int x){
     RG int y=fa[x],z=fa[y],k=ch[y][]==x;
     if (!isroot(y)) ch[z][ch[z][]==y]=x;
     fa[x]=z,ch[y][k^]=ch[x][k],fa[ch[x][k]]=y;
     ch[x][k]=y,fa[y]=x,pushup(y),pushup(x); return;
   }

   il void splay(RG int x){
     RG int top=; st[++top]=x;
     for (RG int i=x;!isroot(i);i=fa[i]) st[++top]=fa[i];
     for (RG int i=top;i;--i) if (rev[st[i]]) pushdown(st[i]);
     while (!isroot(x)){
       RG int y=fa[x],z=fa[y];
       if (!isroot(y)) rotate((ch[z][]==y)^(ch[y][]==x)?x:y);
       rotate(x);
     }
     return;
   }

   il void access(RG int x){
     RG int t=;
     while (x){
       splay(x),ch[x][]=t;
       pushup(x),t=x,x=fa[x];
     }
     return;
   }

   il void makeroot(RG int x){
     access(x),splay(x),rev[x]^=; return;
   }

   il void link(RG int x,RG int y){
     makeroot(x),fa[x]=y; return;
   }

   il void cut(RG int x,RG int y){
     makeroot(x),access(y),splay(y);
     ch[y][]=fa[x]=,pushup(y); return;
   }

   il int query(RG int x,RG int y){
     makeroot(x),access(y),splay(y); return sum[y];
   }

   il int find(RG int x){
     access(x),splay(x);
     while (ch[x][]) x=ch[x][]; return x;
   }

 }G[];

 int main(){
 #ifndef ONLINE_JUDGE
   freopen("network.in","r",stdin);
   freopen("network.out","w",stdout);
 #endif
   n=gi(),m=gi(),c=gi(),Q=gi();
   for (RG int i=;i<=n;++i) val[i]=gi();
   for (RG int i=,u,v,w;i<=m;++i){
     u=gi(),v=gi(),w=gi(); if (u>v) swap(u,v);
     G[w].link(u,v),mp[u][v]=w,++d[u][w],++d[v][w];
   }
   while (Q--){
     RG int op=gi();
     if (!op){
       RG int x=gi(),y=gi();
       for (RG int i=;i<c;++i) G[i].splay(x); val[x]=y;
       for (RG int i=;i<c;++i) G[i].pushup(x);
     } else if (op==){
       RG int u=gi(),v=gi(),w=gi(),k; if (u>v) swap(u,v);
       if (!mp[u].count(v)){ puts("No such edge."); continue; } k=mp[u][v];
       if (k!=w && (d[u][w]>= || d[v][w]>=)) puts("Error 1.");
       else if (k!=w && G[w].find(u)==G[w].find(v)) puts("Error 2."); else{
     RG int k=mp[u][v]; --d[u][k],--d[v][k],++d[u][w],++d[v][w];
     G[k].cut(u,v),G[w].link(u,v),mp[u][v]=w,puts("Success.");
       }
     } else{
       RG int w=gi(),u=gi(),v=gi();
       if (G[w].find(u)!=G[w].find(v)) puts("-1");
       else printf("%d\n",G[w].query(u,v));
     }
   }
   return ;
 }