[LOJ6498] "Yali training 2018 Day2" Farmers

Face questions

solution

Direct violence simulation, the original data can be obtained full marks.

For each point, his father has a limit. Therefore, we only need to determine the limit on the point to the root of the current path can meet if you can.

Consider cross + segment tree to maintain this limit with a tree. Considering the reversing operation, we need to maintain the current range limitations son left the minimum / maximum son and right Min / Max.

Note flipping action will lead to changes in shape of the tree.

code

#include<cstdio>
#include<algorithm>
using namespace std;
namespace io {
    const int SIZE=(1<<21)+1;
    char ibuf[SIZE],*iS,*iT,c;
#define gc()(iS==iT?(iT=(iS=ibuf)+fread(ibuf,1,SIZE,stdin),(iS==iT?EOF:*iS++)):*iS++)
    inline int gi (){
        int x=0,f=1;
        for(c=gc();c<'0'||c>'9';c=gc())if(c=='-')f=-1;
        for(;c<='9'&&c>='0';c=gc()) x=(x<<1)+(x<<3)+(c&15); return x*f;
    }
} using io::gi;
const int N=1e5+5,inf=1<<30;
int n,m,a[N],ls[N],rs[N],size[N],son[N],top[N],dep[N],fa[N],id[N],ed[N],idx[N],tim,rt;
int mxl[N<<2],mnl[N<<2],mxr[N<<2],mnr[N<<2];
bool nr[N],isl[N],rev[N<<2],tg[N<<2];
#define lx (x<<1)
#define rx (x<<1|1)
void dfs(int u)
{
    if(!u) return ; 
    size[u]=1;
    fa[ls[u]]=u,fa[rs[u]]=u;
    dep[ls[u]]=dep[rs[u]]=dep[u]+1;
    dfs(ls[u]),dfs(rs[u]);
    son[u]=(size[ls[u]]>size[rs[u]]?ls[u]:rs[u]);
}
void dfs2(int u, int tp)
{
    if(!u) return ;
    id[u]=++tim;
    top[u]=tp, idx[tim]=u;
    isl[ls[u]]=true;
    if(son[u]==ls[u]) dfs2(ls[u],tp),dfs2(rs[u],rs[u]);
    else dfs2(rs[u],tp),dfs2(ls[u],ls[u]);
    ed[u]=tim;
}
void pushup(int x)
{
    mxl[x]=max(mxl[lx],mxl[rx]);
    mnl[x]=min(mnl[lx],mnl[rx]);
    mxr[x]=max(mxr[lx],mxr[rx]);
    mnr[x]=min(mnr[lx],mnr[rx]);
}
void pushdown(int x)
{
    if(!rev[x]) return ;
    rev[lx]^=1,rev[rx]^=1;
    tg[lx]^=1,tg[rx]^=1;
    swap(mxl[lx],mxr[lx]);
    swap(mnl[lx],mnr[lx]);
    swap(mxl[rx],mxr[rx]);
    swap(mnl[rx],mnr[rx]);
    rev[x]=0;
}
void upd(int x, int u, int w)
{
    if(u==1) mxl[x]=mxr[x]=-1,mnl[x]=mnr[x]=inf;
    else if(isl[u]^tg[x]) mxl[x]=mnl[x]=w,mxr[x]=-1,mnr[x]=inf;
    else mxr[x]=mnr[x]=w,mxl[x]=-1,mnl[x]=inf;
}
void build(int x, int l, int r)
{
    if(l==r)
    {
        upd(x,idx[l],a[fa[idx[l]]]);
        return ;
    }
    int mid=l+r>>1;
    build(lx,l,mid),build(rx,mid+1,r);
    pushup(x);
}
void update(int x, int l, int r, int s, int w)
{
    if(l==r)
    {
        upd(x,idx[l],w);
        return ;
    }
    pushdown(x);
    int mid=l+r>>1;
    s<=mid?update(lx,l,mid,s,w):update(rx,mid+1,r,s,w);
    pushup(x);
}
void rever(int x, int l, int r, int sl, int sr)
{
    if(sl<=l&&r<=sr)
    {
        rev[x]^=1,tg[x]^=1;
        swap(mxl[x],mxr[x]);
        swap(mnl[x],mnr[x]);
        return ;
    }
    pushdown(x);
    int mid=l+r>>1;
    if(sl<=mid) rever(lx,l,mid,sl,sr);
    if(sr>mid) rever(rx,mid+1,r,sl,sr);
    pushup(x);
}
pair<int,int> query(int x, int l, int r, int sl, int sr)
{
    if(sl<=l&&r<=sr) return make_pair(mnl[x],mxr[x]);
    pushdown(x);
    int mid=l+r>>1;
    if(sr<=mid) return query(lx,l,mid,sl,sr);
    else if(sl>mid) return query(rx,mid+1,r,sl,sr);
    else
    {
        pair<int,int> ql=query(lx,l,mid,sl,sr),qr=query(rx,mid+1,r,sl,sr);
        int ans_mnl,ans_mxr;
        ans_mnl=min(ql.first,qr.first);
        ans_mxr=max(ql.second,qr.second);
        return make_pair(ans_mnl,ans_mxr);
    }
}
bool check(int x)
{
    int ans_mnl=inf,ans_mxr=-1,w=a[x];
    while(top[x]^top[rt])
    {
        pair<int,int> q=query(1,1,n,id[top[x]],id[x]);
        ans_mnl=min(ans_mnl,q.first);
        ans_mxr=max(ans_mxr,q.second);
        x=fa[top[x]];
    }
    pair<int,int> q=query(1,1,n,id[rt],id[x]);
    ans_mnl=min(ans_mnl,q.first);
    ans_mxr=max(ans_mxr,q.second);
    return (w<ans_mnl&&w>ans_mxr);
}
int main()
{
    n=gi(),m=gi();
    for(int i=1;i<=n;++i) a[i]=gi(),ls[i]=gi(),rs[i]=gi(),nr[ls[i]]=nr[rs[i]]=true;
    for(int i=1;i<=n;++i) if(!nr[i]) rt=i;
    dfs(rt),dfs2(rt,rt),build(1,1,n);
    while(m--)
    {
        int op=gi(),x=gi();
        if(op==1)
        {
            int w=gi();
            if(ls[x]) update(1,1,n,id[ls[x]],w);
            if(rs[x]) update(1,1,n,id[rs[x]],w);
            a[x]=w;
        }
        if(op==2) rever(1,1,n,id[x]+1,ed[x]);
        if(op==3) puts(check(x)?"YES":"NO");
    }
}

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Origin www.cnblogs.com/farway17/p/10948240.html