Bzoj 3531: [Sdoi2014] Travel

Duty Address: http://www. Lydsy. Com/judgeonline/problem. Php?

id = 3531

Title Effect: See the original title.

Algorithm discussion: Tree chain splitting.

We can.

Code:

#include <cstdio> #include <algorithm> #define N 3000000#define M 30000000#define oo 0x7f7f7f7fusing Namespace Std;int n,q,x,y,mm,tot,digit[10],w[n+10],c[n+10],next[n+10],son[n+10],ed[n+10],fa[n+10],head[n+10], HEAVY[N+10], Size[n+10],deep[n+10],id[n+10],tree1[m+10],tree2[m+10],l[n+10],r[n+10],root[n+10];bool vis[N+10];    Char s[10];void Add (int x,int y) {next[++mm]=son[x];    son[x]=mm; Ed[mm]=y;}    void dfs1 (int x) {vis[x]=1;    Size[x]=1;        for (int i=son[x];i;i=next[i]) {int y=ed[i];            if (!vis[y]) {fa[y]=x;            deep[y]=deep[x]+1;            DFS1 (y);            Size[x]+=size[y];        if (Size[y]>size[heavy[x]]) heavy[x]=y;    }}}void DFS2 (int x) {vis[x]=1;    Id[x]=++tot;    if (!head[x]) head[x]=x;        if (Heavy[x]) {head[heavy[x]]=head[x];    DFS2 (Heavy[x]);        } for (int i=son[x];i;i=next[i]) {int y=ed[i];    if (!vis[y]) dfs2 (y); }}void up (int rt) {TREE1[RT]=TREE1[L[RT]]+TREE1[R[RT]]; Tree2[rt]=max (Tree2[l[rt]],tree2[r[rt]);}    void Modify (int& rt,int lc,int rc,int x,int y) {if (!rt) Rt=++tot;        if (LC==RC) {tree1[rt]=y;        Tree2[rt]=y;    Return    } int mid= (LC+RC)/2;    if (x<=mid) modify (l[rt],lc,mid,x,y);    else modify (r[rt],mid+1,rc,x,y); Up (RT);}    int qsum (int rt,int lc,int rc,int l,int R) {if (!RT) return 0;    if (L==LC && R==RC) return TREE1[RT];    int mid= (LC+RC)/2;    if (R<=mid) return qsum (L[RT],LC,MID,L,R);    if (L>mid) return qsum (R[RT],MID+1,RC,L,R); Return Qsum (L[rt],lc,mid,l,mid) +qsum (r[rt],mid+1,rc,mid+1,r);}    int Qmax (int rt,int lc,int rc,int l,int R) {if (!RT) return 0;    if (L==LC && R==RC) return TREE2[RT];    int mid= (LC+RC)/2;    if (R<=mid) return Qmax (L[RT],LC,MID,L,R);    if (L>mid) return Qmax (R[RT],MID+1,RC,L,R); Return Max (Qmax (L[rt],lc,mid,l,mid), Qmax (R[rt],mid+1,rc,mid+1,r));}    int qs (int x,int y) {int ans=0,c=c[x]; while (Head[x]!=head[y]) {if (dEep[head[x]]<deep[head[y]]) swap (x, y);        Ans+=qsum (Root[c],1,n,id[head[x]],id[x]);    X=FA[HEAD[X]];    } if (Deep[x]>deep[y]) swap (x, y);    Ans+=qsum (Root[c],1,n,id[x],id[y]); return ans;}    int QM (int x,int y) {int ans=-oo,c=c[x];        while (Head[x]!=head[y]) {if (deep[head[x]]<deep[head[y])) swap (x, y);        Ans=max (Ans,qmax (root[c],1,n,id[head[x]],id[x));    X=FA[HEAD[X]];    } if (Deep[x]>deep[y]) swap (x, y);    Ans=max (Ans,qmax (root[c],1,n,id[x],id[y)); return ans;}    int main () {#ifndef Online_judge freopen ("3531.in", "R", stdin);    Freopen ("3531.out", "w", stdout);    #endif scanf ("%d%d", &n,&q);    for (int i=1;i<=n;++i) scanf ("%d%d", &w[i],&c[i]);        for (int i=1;i<n;++i) {scanf ("%d%d", &x,&y);        Add (x, y);    Add (y,x);    } DFS1 (1);    for (int i=1;i<=n;++i) vis[i]=0;    DFS2 (1);    tot=0;    for (int i=1;i<=n;++i) modify (Root[c[i]],1,n,id[i],w[i]); for (int i=1;i<=q;++i){scanf ("%s%d%d", s,&x,&y);                if (s[0]== ' C ') if (s[1]== ' C ') {modify (root[c[x]],1,n,id[x],0);                Modify (Root[y],1,n,id[x],w[x]);            C[x]=y;                } else{Modify (Root[c[x]],1,n,id[x],y);            W[x]=y;        } else if (s[1]== ' s ') printf ("%d\n", QS (x, y));    else printf ("%d\n", QM (x, y)); } return 0;}

by Charlie Pan

Mar 14,2014



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Bzoj 3531: [Sdoi2014] Travel