SDOI2014 旅行

传送门

省选前水一发

这题一开始看标签是主席树……后来……这题和主席树有啥关系……
可以想到对于每种宗教用树剖+线段树维护即可。然后因为空间不够要动态开点。然后改宗教，改评级的，把原来的点删了再插一个新点就可以了。查询最大值，和就直接线段树维护。
当树剖板子练习了。

#include<bits/stdc++.h>
#define rep(i,a,n) for(int i = a;i <= n;i++)
#define per(i,n,a) for(int i = n;i >= a;i--)
#define enter putchar('\n')
#define pr pair<int,int>
#define mp make_pair
#define fi first
#define sc second
using namespace std;
typedef long long ll;
const int M = 100005;
const int N = 2000005;
const int INF = 0x3f3f3f3f;
 
int read()
{
   int ans = 0,op = 1;char ch = getchar();
   while(ch < '0' || ch > '9') {if(ch == '-') op = -1;ch = getchar();}
   while(ch >='0' && ch <= '9') ans = ans * 10 + ch - '0',ch = getchar();
   return ans * op;
}

int n,m,w[M],c[M],head[M],ecnt,dep[M],hson[M],top[M],idx,dfn[M],rk[M],fa[M];
int x,y,size[M],cnt,root[M],k,q;
char ch[5];

struct tree
{
   int lc,rc,val,sum;
}t[M<<5];

struct edge
{
   int next,to,from;
}e[M<<1];

void add(int x,int y){e[++ecnt] = {head[x],y,x},head[x] = ecnt;}

void dfs1(int x,int f)
{
   dep[x] = dep[f] + 1,size[x] = 1,fa[x] = f;
   for(int i = head[x];i;i = e[i].next)
   {
      if(e[i].to == f) continue;
      dfs1(e[i].to,x);
      size[x] += size[e[i].to];
      if(size[e[i].to] > size[hson[x]]) hson[x] = e[i].to;
   }
}

void dfs2(int x,int t)
{
   dfn[x] = ++idx,rk[idx] = x,top[x] = t;
   if(hson[x]) dfs2(hson[x],t);
   for(int i = head[x];i;i = e[i].next)
   {
      if(e[i].to == hson[x] || e[i].to == fa[x]) continue;
      dfs2(e[i].to,e[i].to);
   }
}

void pushup(int p)
{
   t[p].val = max(t[t[p].lc].val,t[t[p].rc].val);
   t[p].sum = t[t[p].lc].sum + t[t[p].rc].sum;
}
void pushdown(int p){t[p].sum = t[p].val = 0;}

void insert(int &p,int l,int r,int pos,int val)
{
   if(!p) p = ++cnt;
   if(l == r) {t[p].sum = t[p].val = val;return;}
   int mid = (l+r) >> 1;
   if(pos <= mid) insert(t[p].lc,l,mid,pos,val);
   else insert(t[p].rc,mid+1,r,pos,val);
   pushup(p);
}

void del(int &p,int l,int r,int pos)
{
   if(!p) return;
   if(l == r) {pushdown(p);return;}
   int mid = (l+r) >> 1;
   if(pos <= mid) del(t[p].lc,l,mid,pos);
   else del(t[p].rc,mid+1,r,pos);
   pushup(p);
}

int query(int &p,int l,int r,int kl,int kr)
{
   if(!p) return 0;
   if(l == kl && r == kr) return t[p].sum;
   int mid = (l+r) >> 1;
   if(kr <= mid) return query(t[p].lc,l,mid,kl,kr);
   else if(kl > mid) return query(t[p].rc,mid+1,r,kl,kr);
   else return query(t[p].lc,l,mid,kl,mid) + query(t[p].rc,mid+1,r,mid+1,kr);
}

int ask(int &p,int l,int r,int kl,int kr)
{
   if(!p) return 0;
   if(l == kl && r == kr) return t[p].val;
   int mid = (l+r) >> 1;
   if(kr <= mid) return ask(t[p].lc,l,mid,kl,kr);
   else if(kl > mid) return ask(t[p].rc,mid+1,r,kl,kr);
   else return max(ask(t[p].lc,l,mid,kl,mid),ask(t[p].rc,mid+1,r,mid+1,kr));
}

int srange(int x,int y)
{
   int cur = 0,k = c[x];
   while(top[x] != top[y])
   {
      if(dep[top[x]] < dep[top[y]]) swap(x,y);
      cur += query(root[k],1,n,dfn[top[x]],dfn[x]);
      x = fa[top[x]];
   }
   if(dep[x] > dep[y]) swap(x,y);
   cur += query(root[k],1,n,dfn[x],dfn[y]);
   return cur;
}

int mrange(int x,int y)
{
   int cur = 0,k = c[x];
   while(top[x] != top[y])
   {
      if(dep[top[x]] < dep[top[y]]) swap(x,y);
      cur = max(cur,ask(root[k],1,n,dfn[top[x]],dfn[x]));
      x = fa[top[x]];
   }
   if(dep[x] > dep[y]) swap(x,y);
   cur = max(cur,ask(root[k],1,n,dfn[x],dfn[y]));
   return cur;
}

int main()
{
   n = read(),q = read();
   rep(i,1,n) w[i] = read(),c[i] = read();
   rep(i,1,n-1) x = read(),y = read(),add(x,y),add(y,x);
   dfs1(1,0),dfs2(1,1);
   rep(i,1,n) insert(root[c[i]],1,n,dfn[i],w[i]);
   while(q--)
   {
      scanf("%s",ch);
      if(ch[1] == 'C')
      {
	 x = read(),k = read();
	 del(root[c[x]],1,n,dfn[x]),c[x] = k;
	 insert(root[c[x]],1,n,dfn[x],w[x]);
      }
      if(ch[1] == 'W')
      {
	 x = read(),k = read();
	 del(root[c[x]],1,n,dfn[x]),w[x] = k;
	 insert(root[c[x]],1,n,dfn[x],w[x]);
      }
      if(ch[1] == 'S')
      {
	 x = read(),y = read();
	 printf("%d\n",srange(x,y));
      }
      if(ch[1] == 'M')
      {
	 x = read(),y = read();
	 printf("%d\n",mrange(x,y));
      }
   }
   return 0;
}