bzoj 3531: [Sdoi2014]旅行 树链剖分

       树剖后直接对每一个宗教建立一颗线段树维护就好了。

AC代码：

#include<iostream>#include<cstdio>#include<cstring>#define N 100005#define M 10000005using namespace std;int n,m,trtot,tot,dfsclk,a[N],b[N],d[N],fa[N],fst[N],pnt[N<<1],nxt[N<<1],pos[N],anc[N],sz[N],son[N];struct node{ int x,y; }val[M]; int rt[N],ls[M],rs[M];int read(){int x=0; char ch=getchar();while (ch<'0' || ch>'9') ch=getchar();while (ch>='0' && ch<='9'){ x=x*10+ch-'0'; ch=getchar(); }return x;}void add(int x,int y){pnt[++tot]=y; nxt[tot]=fst[x]; fst[x]=tot;}void dfs(int x){int p; sz[x]=1;for (p=fst[x]; p; p=nxt[p]){int y=pnt[p];if (y!=fa[x]){fa[y]=x; d[y]=d[x]+1;dfs(y); sz[x]+=sz[y];if (sz[y]>sz[son[x]]) son[x]=y;}}}void divide(int x,int tp){anc[x]=tp; pos[x]=++dfsclk; int p;if (son[x]) divide(son[x],tp);for (p=fst[x]; p; p=nxt[p]){int y=pnt[p];if (y!=fa[x] && y!=son[x]) divide(y,y);}}void mdy(int &k,int l,int r,int x,int y){if (!k) k=++trtot;if (l==r){ val[k].x=val[k].y=y; return; }int mid=(l+r)>>1;if (x<=mid) mdy(ls[k],l,mid,x,y); else mdy(rs[k],mid+1,r,x,y);val[k].x=val[ls[k]].x+val[rs[k]].x; val[k].y=max(val[ls[k]].y,val[rs[k]].y);}node qry(int k,int l,int r,int x,int y){if (l==x && r==y || !k) return val[k]; int mid=(l+r)>>1;if (y<=mid) return qry(ls[k],l,mid,x,y); elseif (x>mid) return qry(rs[k],mid+1,r,x,y); else{node t1=qry(ls[k],l,mid,x,mid),t2=qry(rs[k],mid+1,r,mid+1,y);t1.x+=t2.x; t1.y=max(t1.y,t2.y); return t1;}}int main(){n=read(); m=read(); int i,x,y;for (i=1; i<=n; i++){a[i]=read(); b[i]=read();}for (i=1; i<n; i++){x=read(); y=read();add(x,y); add(y,x);}dfs(1); divide(1,1);for (i=1; i<=n; i++) mdy(rt[b[i]],1,n,pos[i],a[i]);char ch; int ans,k;while (m--){ch=getchar(); while (ch<'A' || ch>'Z') ch=getchar(); ch=getchar();x=read(); y=read();if (ch=='C'){mdy(rt[b[x]],1,n,pos[x],0); b[x]=y;mdy(rt[y],1,n,pos[x],a[x]);} else if (ch=='W'){a[x]=y; mdy(rt[b[x]],1,n,pos[x],y);} else if (ch=='S'){ans=0; k=b[x];for (; anc[x]!=anc[y]; x=fa[anc[x]]){if (d[anc[x]]<d[anc[y]]) swap(x,y);ans+=qry(rt[k],1,n,pos[anc[x]],pos[x]).x;}if (pos[x]>pos[y]) swap(x,y); ans+=qry(rt[k],1,n,pos[x],pos[y]).x;printf("%d\n",ans);} else if (ch=='M'){ans=0; k=b[x];for (; anc[x]!=anc[y]; x=fa[anc[x]]){if (d[anc[x]]<d[anc[y]]) swap(x,y);ans=max(ans,qry(rt[k],1,n,pos[anc[x]],pos[x]).y);}if (pos[x]>pos[y]) swap(x,y); ans=max(ans,qry(rt[k],1,n,pos[x],pos[y]).y);printf("%d\n",ans);}}return 0;}

by lych

2016.4.4