P2146 [NOI2015]软件包管理器

P2146 [NOI2015]软件包管理器

一道树链剖分……

还算是比较裸的树剖w

对于查询（影响数）的话只需要查询原本根节点值与现根节点值差异就可以了

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <cmath>
using namespace std;
#define MAXN 100233
//data
int n;

int ans[MAXN<<2],tag[MAXN<<2]={};

struct qwq
{
    int nex,to;
}e[MAXN<<1];

int h[MAXN],son[MAXN],siz[MAXN],fa[MAXN],top[MAXN],id[MAXN],dep[MAXN];

int tot=0,cnt=0;
//data_end.
void add(int x,int y)
{
    e[++tot].to=y;
    e[tot].nex=h[x];
    h[x]=tot;
}
//dfs<<1
inline void dfs_fir(int x,int f,int dept)
{
    dep[x]=dept;
    fa[x]=f;
    siz[x]=1;
    int maxn=-1;
    for (int i=h[x],y;i;i=e[i].nex)
    {
        y=e[i].to;
        if (y==f) continue;
        dfs_fir(y,x,dept+1);
        siz[x]+=siz[y];
        if (siz[y]>maxn)
        {
            son[x]=y;
            maxn=siz[y];
        }
    }
}
inline void dfs_sec(int x,int ft)
{
    id[x]=++cnt;
    top[x]=ft;
    if (!son[x]) return;
    dfs_sec(son[x],ft);
    int y;
    for (int i=h[x];i;i=e[i].nex)
    {
        y=e[i].to;
        if (y==fa[x]||y==son[x]) continue;
        dfs_sec(y,y);
    }
}
//dfs_end.

//segment_tree
#define ll long long
#define leftson cur<<1
#define rightson cur<<1|1
#define mid ((l+r)>>1)
#define push_up ans[cur]=ans[leftson]+ans[rightson]
#define push_down lazyadd(leftson,l,mid,tag[cur]); lazyadd(rightson,mid+1,r,tag[cur]); tag[cur]=-1
void lazyadd(int cur,int l,int r,int del)
{
    if (del==-1) return;
    ans[cur]=(r-l+1)*del;
    tag[cur]=del;
}
inline void change(int adl,int adr,int cur,int l,int r,int del)
{
    if (adl<=l&&r<=adr)
    {
        ans[cur]=(r-l+1)*del;
        tag[cur]=del;
        return;
    }
    push_down;
    if (adl<=mid) change(adl,adr,leftson,l,mid,del);
    if (adr>mid) change(adl,adr,rightson,mid+1,r,del);
    push_up;
}
#undef ll
//segment_tree_end.
void upd(int x,int y,int del)
{
    while (top[x]!=top[y])
    {
        if (dep[top[x]]<dep[top[y]]) swap(x,y);
        change(id[top[x]],id[x],1,1,n,del);
        x=fa[top[x]];
    }
    if (dep[x]>dep[y]) swap(x,y);
    change(id[x],id[y],1,1,n,del);
}

int main()
{
    scanf("%d",&n);
    int a;
    for (int i=2;i<=n;i++)
    {
        scanf("%d",&a);
        add(a+1,i);
    }
    for (int i=1;i<=(n<<2);i++)
    {
        tag[i]=-1;
    }
    dfs_fir(1,1,1);
    dfs_sec(1,1);
    int q;
    scanf("%d",&q);
    string s;
    int TAT;
    for (int i=1;i<=q;i++)
    {
        cin>>s;
        scanf("%d",&a);
        a++;
        TAT=ans[1];
        if (s[0]=='u')
        {
            change(id[a],id[a]+siz[a]-1,1,1,n,0);
            printf("%d\n",abs(TAT-ans[1]));
            continue;
        }
        upd(1,a,1);
        printf("%d\n",abs(TAT-ans[1]));
    }
}

残废了。。。