UOJ274 [清华集训2016] 温暖会指引我们前行 【LCT】【最大生成树】

题目分析：

差评，最大生成树裸题。hack数据还卡常。

代码：

 #include<bits/stdc++.h>
 using namespace std;

 const int maxn = ;

 struct LCT{
     int fa[maxn],lazy[maxn],ch[maxn][],d1[maxn],d2[maxn];
     int val[maxn],tot[maxn],num;
     stack<int> sta;
     void push_up(int now){
     val[now] = min(d1[now],min(val[ch[now][]],val[ch[now][]]));
     tot[now] = d2[now] + tot[ch[now][]] + tot[ch[now][]];
     }
     void push_down(int now){
     if(lazy[now]){
         swap(ch[now][],ch[now][]);
         lazy[now]=;
         lazy[ch[now][]] ^= ; lazy[ch[now][]] ^= ;
         lazy[] = ;
     }
     }
     int is_root(int now){return !(ch[fa[now]][]==now||ch[fa[now]][]==now);}
     void r0(int now,int dr){
     int ff = fa[now],gf = fa[ff],son = ch[now][dr];
     int flag = is_root(ff);
     ch[ff][dr^] = son; fa[son] = ff;
     ch[now][dr] = ff; fa[ff] = now;
     fa[now] = gf;
     if(!flag){if(ch[gf][] == ff) ch[gf][] = now; else ch[gf][] = now;}
     push_up(ff); push_up(now);
     fa[] = ;ch[][] = ch[][] = ;
     }
     void splay(int now){
     int pp = now;
     while(!is_root(pp)) sta.push(pp),pp = fa[pp];
     sta.push(pp);
     while(!sta.empty()) push_down(sta.top()),sta.pop();
     while(!is_root(now)){
         if(is_root(fa[now])){
         if(ch[fa[now]][] == now) r0(now,); else r0(now,);
         }else{
         int ff = fa[now],gf = fa[ff];
         int alpha = ch[gf][]==ff,beta = ch[ff][]==now;
         if(alpha^beta) r0(now,beta),r0(now,alpha);
         else r0(ff,alpha),r0(now,beta);
         }
     }
     }
     void access(int now){
     splay(now);ch[now][] = ;push_up(now);
     while(fa[now]){
         int nxt=fa[now];splay(nxt);ch[nxt][]=now; push_up(nxt); now=nxt;
     }
     }
     void make_root(int now){
     access(now);
     splay(now);
     lazy[now] ^= ;
     }
     void cut(int u,int v){
     make_root(u); access(v); splay(u);
     fa[v] = ;
     if(ch[u][] == v) ch[u][] = ; else ch[u][] = ;
     push_up(u);
     }
     void link(int u,int v){make_root(u); fa[u] = v;}
     int lft(int dt){
     splay(dt);
     if(lazy[dt]) push_down(dt);
     while(ch[dt][]){
         dt = ch[dt][];
         if(lazy[dt]) push_down(dt);
     }
     return dt;
     }
     int find_min(int now){
     splay(now);
     while(d1[now] != val[now]){
         if(val[ch[now][]] == val[now]) now = ch[now][];
         else now = ch[now][];
     }
     return now;
     }
 }T;

 int n,m,pre[maxn];

 struct edge{int from,to,tmp,len;}edges[maxn];

 char str[];

 int found(int x){
     int rx = x; while(pre[rx] != rx) rx = pre[rx];
     while(pre[x]!=rx){int tt = x; pre[x] = rx; x = tt;}
     return rx;
 }

 void work(){
     T.d1[] = 2e9;T.val[] = 2e9;T.d2[] = ;
     for(int i=;i<=n;i++){T.num++;T.d1[i] = 2e9; T.val[i] = 2e9; pre[i] = i;}
     for(int i=;i<=m;i++){
     scanf("%s",str);
     if(str[] == 'f'){
         int id;scanf("%d",&id);
         scanf("%d%d",&edges[id].from,&edges[id].to);
         scanf("%d%d",&edges[id].tmp,&edges[id].len);
         edges[id].from++;edges[id].to++;
         T.d1[n+id+] = edges[id].tmp; T.d2[n+id+] = edges[id].len;
         T.val[n+id+] = edges[id].tmp; T.tot[n+id+] = edges[id].len;
         T.make_root(edges[id].from);
         T.access(edges[id].to);
          int pd = T.lft(edges[id].to);
         if(pd == edges[id].from){
         if(T.val[edges[id].to] > edges[id].tmp) continue;
         int pla = T.find_min(edges[id].to);
         T.make_root(pla);T.cut(pla,edges[pla-n-].from);
         T.cut(pla,edges[pla-n-].to);
         }
         T.link(edges[id].from,n+id+);T.link(edges[id].to,n+id+);
         pre[found(edges[id].from)] = found(edges[id].to);
     }else{
         if(str[] == 'm'){
         int u,v; scanf("%d%d",&u,&v); v++;u++;
         if(found(u) != found(v)){puts("-1");continue;}
         T.make_root(u);    T.access(v); T.splay(v);
         printf("%d\n",T.tot[v]);
         }else{
         int id,l; scanf("%d%d",&id,&l);
         T.make_root(n+id+); T.d2[n+id+] = l;
         T.push_up(n+id+);
         }
     }
     }
 }

 int main(){
     scanf("%d%d",&n,&m);
     work();
     return ;
 }