SPOJ.COT2 Count on a tree II(树上莫队)

题目链接(同上一题苹果树)

为什么第10个点T了一晚上。。
下面那个却AC了？跑的也不慢。

TLE:

/*
在DFS序做莫队
当一个点不是另一个点的LCA时，需要加上它们LCA的贡献
*/
#include <cmath>
#include <cstdio>
#include <cctype>
#include <algorithm>
#define gc() getchar()
//#define gc() (SS==TT&&(TT=(SS=IN)+fread(IN,1,MAXIN,stdin),SS==TT)?EOF:*SS++)
const int N=5e4+5,M=1e5+5,MAXIN=2e6;

int n,m,size,Enum,H[N],nxt[N<<1],to[N<<1],dep[N],fa[N],top[N],son[N],sz[N];
int Now,Ans[M],seq[N<<1],in[N],out[N],id,A[N],ref[N],cnt,tm[N];
//char IN[MAXIN],*SS=IN,*TT=IN;
bool vis[N];
struct Ques
{
    int l,r,lca,id;
    bool operator <(const Ques &a)const{
        return l/size<a.l/size?r<a.r:l/size<a.l/size;
    }
}q[M];

//inline int read()
//{
//  int now=0,f=1;register char c=gc();
//  for(;!isdigit(c);c=gc()) if(c=='-') f=-1;
//  for(;isdigit(c);now=now*10+c-'0',c=gc());
//  return now*f;
//}
inline void AddEdge(int u,int v)
{
    to[++Enum]=v, nxt[Enum]=H[u], H[u]=Enum;
    to[++Enum]=u, nxt[Enum]=H[v], H[v]=Enum;
}
int Find(int x)
{
    int l=1,r=cnt,mid;
    while(l<r)
        if(ref[mid=l+r>>1]>=x) r=mid;
        else l=mid+1;
    return l;
}
void Discrete()
{
//  for(int i=1; i<=n; ++i) A[i]=ref[i]=read();
    for(int i=1; i<=n; ++i) scanf("%d",&A[i]),ref[i]=A[i];
    std::sort(ref+1,ref+1+n);
    cnt=1;
    for(int i=2; i<=n; ++i)
        if(ref[i]!=ref[i-1]) ref[++cnt]=ref[i];
    for(int i=1; i<=n; ++i) A[i]=Find(A[i]);
}
void Pre_DFS(int x)
{
    in[x]=++id, seq[id]=x, sz[x]=1;
    int mx=0;
    for(int v,i=H[x]; i; i=nxt[i])
        if((v=to[i])!=fa[x])
        {
            fa[v]=x, dep[v]=dep[x]+1, Pre_DFS(v), sz[x]+=sz[v];
            if(sz[v]>mx) mx=sz[v],son[x]=v;
        }
    out[x]=++id, seq[id]=x;
}
void DFS2(int x,int tp)
{
    top[x]=tp;
    if(son[x])
    {
        DFS2(son[x],tp);
        for(int i=H[x]; i; i=nxt[i])
            if(to[i]!=fa[x]&&to[i]!=son[x])
                DFS2(to[i],to[i]);
    }
}
int Query_LCA(int x,int y)
{
    while(top[x]!=top[y])
    {
        if(dep[top[x]]<dep[top[y]]) std::swap(x,y);
        x=fa[top[x]];
    }
    return dep[x]>dep[y]?y:x;
}
void Calc(int p)
{
    if(vis[p])
        if(!--tm[A[p]]) --Now;
        else ;
    else if(++tm[A[p]]==1) ++Now;
    vis[p]^=1;
}

int main()
{
//  n=read(),m=read();
    scanf("%d%d",&n,&m);
    Discrete();
//  for(int u,v,i=1; i<n; ++i) u=read(),v=read(),AddEdge(u,v);
    for(int u,v,i=1; i<n; ++i) scanf("%d%d",&u,&v),AddEdge(u,v);
    Pre_DFS(1), DFS2(1,1);
    for(int u,v,w,i=1; i<=m; ++i)
    {
//      u=read(),v=read(),w=Query_LCA(u,v);
        scanf("%d%d",&u,&v),w=Query_LCA(u,v);
        q[i].id=i;//这要在continue前面。。
        if(u==v) {q[i].lca=-1; continue;}
        if(in[u]>in[v]) std::swap(u,v);
        if(w==u) q[i].l=in[w],q[i].r=in[v],q[i].lca=0;//这部分的LCA不能和u=v时用一样的！
//      else if(w==v) q[i].r=in[w],q[i].r=in[u],q[i].lca=0;
        else q[i].l=out[u],q[i].r=in[v],q[i].lca=in[w];//in[w] not w!
    }
    size=sqrt(id), std::sort(q+1,q+1+m);
    for(int l=1,r=0,i=1; i<=m; ++i)
        if(q[i].lca==-1) Ans[q[i].id]=1;
        else
        {
            while(l<q[i].l) Calc(seq[l++]);
            while(l>q[i].l) Calc(seq[--l]);
            while(r<q[i].r) Calc(seq[++r]);
            while(r>q[i].r) Calc(seq[r--]);
            if(q[i].lca) Calc(seq[q[i].lca]);//seq[in[lca]] not in[lca]!
            Ans[q[i].id]=Now;
            if(q[i].lca) Calc(seq[q[i].lca]);
        }
    for(int i=1; i<=m; ++i) printf("%d\n",Ans[i]);

    return 0;
}

AC: 2.21s 8.5M

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

typedef long long ll;
const int N = 50010;
struct edge
{
    int to, next;
}g[N*2];
int n, m, unit;
struct node
{
    int l, r, anc, id;
    bool operator <(const node &b)const {return l/unit != b.l/unit ? l/unit < b.l/unit : r < b.r;}
}q[N*2];
int arr[N], ref[N];
int cnt, head[N];
int dep[N];
int in[N], out[N], seq[N*2], num;
int res[N*2], tmp, ver[N];
bool vis[N];
void add_edge(int v, int u)
{
    g[cnt].to = u, g[cnt].next = head[v], head[v] = cnt++;
}
void dfs(int v)
{
    in[v] = ++num;
    seq[num] = v;
    for(int i = head[v]; i != -1; i = g[i].next)
    {
        int u = g[i].to;
        if(! dep[u])
            dep[u] = dep[v] + 1, dfs(u);
    }
    out[v] = ++num;
    seq[num] = v;
}
namespace Subd
{
    int dep[N],fa[N],top[N],son[N],sz[N];
    void Pre_DFS(int x)
    {
        sz[x]=1;
        int mx=0;
        for(int v,i = head[x]; i != -1; i = g[i].next)
            if((v=g[i].to)!=fa[x])
            {
                fa[v]=x, dep[v]=dep[x]+1, Pre_DFS(v), sz[x]+=sz[v];
                if(sz[v]>mx) mx=sz[v],son[x]=v;
            }
    }
    void DFS2(int x,int tp)
    {
        top[x]=tp;
        if(son[x])
        {
            DFS2(son[x],tp);
            for(int v,i = head[x]; i != -1; i = g[i].next)
                if((v=g[i].to)!=fa[x]&&v!=son[x])
                    DFS2(v,v);
        }
    }
    int Query_LCA(int x,int y)
    {
        while(top[x]!=top[y])
        {
            if(dep[top[x]]<dep[top[y]]) std::swap(x,y);
            x=fa[top[x]];
        }
        return dep[x]>dep[y]?y:x;
    }
}
void Calc(int p)
{
    if(vis[p])
        if(!--ver[arr[p]]) --tmp;
        else ;
    else if(++ver[arr[p]]==1) ++tmp;
    vis[p]^=1;
}
int tot;
int Find(int x)
{
    int l=1,r=tot,mid;
    while(l<r)
        if(ref[mid=l+r>>1]>=x) r=mid;
        else l=mid+1;
    return l;
}
void Discrete()
{
    for(int i=1; i<=n; ++i) ref[i]=arr[i];
    sort(ref+1,ref+1+n);
    tot=1;
    for(int i=2; i<=n; ++i)
        if(ref[i]!=ref[i-1]) ref[++tot]=ref[i];
    for(int i=1; i<=n; ++i) arr[i]=Find(arr[i]);
}
//bool cmp(node a, node b){return a.l/unit != b.l/unit ? a.l/unit < b.l/unit : a.r < b.r;}

void solve()
{
    int a, b;
    for(int i = 1; i <= n; i++)
        scanf("%d", &arr[i]);
    Discrete();
    cnt = 0;
    memset(head, -1, sizeof head);
    for(int i = 1; i <= n - 1; i++) //存树
        scanf("%d%d", &a, &b), add_edge(a, b), add_edge(b, a);
    memset(dep, 0, sizeof dep);
    dep[1] = 1;
    num = 0;
    dfs(1);
    Subd::Pre_DFS(1), Subd::DFS2(1,1);
    for(int u,v,i = 1; i <= m; i++)
    {
        scanf("%d%d", &u, &v);
        q[i].id = i;
        if(u == v) q[i].anc = -1; //特殊标记，此时公共祖先应该为1
        else
        {
            int w=Subd::Query_LCA(u,v);
            if(in[u]>in[v]) swap(u,v);
            if(w==u) q[i].l=in[w],q[i].r=in[v],q[i].anc=0;
            else q[i].l=out[u],q[i].r=in[v],q[i].anc=w;
        }
    }
    unit = sqrt(num);
    sort(q + 1, q + 1 + m);//分块排序
    int l = 1, r = 0;
    tmp = 0;
    for(int i = 1; i <= m; i++)
        if(q[i].anc==-1) res[q[i].id]=1;
        else
        {
            while(l<q[i].l) Calc(seq[l++]);
            while(l>q[i].l) Calc(seq[--l]);
            while(r<q[i].r) Calc(seq[++r]);
            while(r>q[i].r) Calc(seq[r--]);
            if(q[i].anc>0) Calc(seq[in[q[i].anc]]);
            res[q[i].id]=tmp;
            if(q[i].anc>0) Calc(seq[in[q[i].anc]]);
        }
    for(int i = 1; i <= m; i++) printf("%d\n", res[i]);
}
int main()
{
    scanf("%d%d", &n, &m);
    solve();
    return 0;
}

原文地址：https://www.cnblogs.com/SovietPower/p/8476895.html