BZOJ1036 [ZJOI2008]树的统计Count

树链剖分裸题。
题目链接

#include<iostream>#include<cstdio>#include<cstring>#include<cmath>#include<algorithm>#define N 30500using namespace std;int n,tot,lable,Next[N*2],head[N*2],tree[N*2],a[N],m,fa[N],dep[N],son[N],size[N],tid[N],number[N];int top[N],Max[N*8],sum[N*8];bool visit[N];void add(int x,int y){    tot++;    Next[tot]=head[x];    head[x]=tot;    tree[tot]=y;}void dfs(int x,int depth,int father){    visit[x]=true;fa[x]=father;dep[x]=depth;son[x]=0;size[x]=1;    int maxsize=0;    for (int i=head[x];i;i=Next[i])    if (!visit[tree[i]])    {        dfs(tree[i],depth+1,x);        size[x]+=size[tree[i]];        if (size[tree[i]]>maxsize)        {            maxsize=size[tree[i]];            son[x]=tree[i];        }    }}void dfs1(int x,int ancestor){    visit[x]=true;tid[x]=++lable;number[lable]=x;top[x]=ancestor;    if (son[x]!=0) dfs1(son[x],ancestor);    for (int i=head[x];i;i=Next[i])        if (!visit[tree[i]]) dfs1(tree[i],tree[i]);}void up(int x){    Max[x]=max(Max[x*2],Max[x*2+1]);    sum[x]=sum[x*2]+sum[x*2+1];}void build(int l,int r,int id){    Max[id]=-1<<29;sum[id]=0;    if (l==r)    {        Max[id]=sum[id]=a[number[l]];        return;    }    int mid=(l+r)/2;    build(l,mid,id*2);    build(mid+1,r,id*2+1);    up(id);}void change(int x,int l,int r,int id,int d){    if (l>x||r<x) return;    if (l==r&&l==x)     {        Max[id]=sum[id]=d;        return;    }    int mid=(l+r)/2;    change(x,l,mid,id*2,d);    change(x,mid+1,r,id*2+1,d);    up(id);}int query(int x,int y,int id,int l,int r,int q){    if (l>y||r<x)     {        if (q==0) return -1<<29;else return 0;    }    if (x<=l&&r<=y)     {        if (q==0) return Max[id];else return sum[id];    }    int mid=(l+r)/2;    if (q==0) return max(query(x,y,id*2,l,mid,q),query(x,y,id*2+1,mid+1,r,q));        else return query(x,y,id*2,l,mid,q)+query(x,y,id*2+1,mid+1,r,q);    up(id);}int Query(int x,int y,int q){    int ans;    if (q==0) ans=-1<<29;else ans=0;    while (top[x]!=top[y])    {        if (dep[top[x]]<dep[top[y]]) swap(x,y);        if (q==0) ans=max(ans,query(tid[top[x]],tid[x],1,1,n,0));            else ans+=query(tid[top[x]],tid[x],1,1,n,1);        x=fa[top[x]];    }    if (dep[x]>dep[y]) swap(x,y);    if (q==0) ans=max(ans,query(tid[x],tid[y],1,1,n,0));            else ans+=query(tid[x],tid[y],1,1,n,1);    return ans;}int main(){    scanf("%d",&n);    tot=lable=0;    for (int i=1;i<n;i++)    {        int x,y;        scanf("%d%d",&x,&y);        add(x,y);add(y,x);    }    for (int i=1;i<=n;i++) scanf("%d",&a[i]);    scanf("%d",&m);    for (int i=1;i<=n;i++) visit[i]=false;    dfs(1,1,0);    for (int i=1;i<=n;i++) visit[i]=false;    dfs1(1,1);    build(1,n,1);    char s[100];    for (int i=1;i<=m;i++)    {        int x,y;        scanf("%s%d%d",s,&x,&y);        if (s[0]=='C') change(tid[x],1,n,1,y);        if (s[1]=='M') printf("%d\n",Query(x,y,0));        if (s[1]=='S') printf("%d\n",Query(x,y,1));    }    return 0;}