Submission #839841

#	Time	Username	Problem	Language	Result	Execution time	Memory
839841		TheUnknown	Global Warming (CEOI18_glo)	C++14	100 / 100	194 ms	20944 KiB

glo

#include<bits/stdc++.h>

using namespace std;
const int maxn=2e5+3,oo=2e9+3;
int a[maxn],n,x,subx[maxn],dpfor[maxn],dpback[maxn];
struct segtree
{
    int st[maxn<<3];
    void upd(int id,int l,int r,int p,int x)
    {
        if(l==r)
        {
            st[id]=max(st[id],x);
            return;
        }
        int mid=(l+r)>>1;
        if(p<=mid) upd(id<<1,l,mid,p,x);
        else upd(id<<1|1,mid+1,r,p,x);
        st[id]=max(st[id<<1],st[id<<1|1]);
    }
    void update(int p,int x)
    {
        upd(1,1,n<<1,p,x);
    }
    int gt(int id,int l,int r,int u,int v)
    {
        if(r<u||v<l) return 0;
        if(u<=l&&r<=v) return st[id];
        int mid=(l+r)>>1;
        return max(gt(id<<1,l,mid,u,v),gt(id<<1|1,mid+1,r,u,v));
    }
    int get(int u,int v)
    {
        if(u>v) return 0;
        return gt(1,1,n<<1,u,v);
    }
}forw,backw,save;
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>n>>x;
    vector<pair<int,int>> cmpress;
    for(int i=1;i<=n;++i)
    {
        cin>>a[i];
        subx[i]=a[i]-x;
        cmpress.push_back({a[i],i});
        cmpress.push_back({subx[i],i+maxn});
    }
    sort(cmpress.begin(),cmpress.end());
    int currval=-oo,reval=0;
    for(auto t:cmpress)
    {
        if(currval!=t.first)
        {
            ++reval;
            currval=t.first;
        }
        if(t.second>maxn) subx[t.second-maxn]=reval;
        else a[t.second]=reval;
    }
    for(int i=1;i<=n;++i)
    {
        dpfor[i]=forw.get(1,a[i]-1)+1;
        forw.update(a[i],dpfor[i]);
    }
    for(int i=n;i>0;--i)
    {
        dpback[i]=backw.get(a[i]+1,n<<1)+1;
        backw.update(a[i],dpback[i]);
    }
    int ans=0;
    for(int i=n;i>0;--i)
    {
        //cout<<i<<' '<<dpfor[i]<<' '<<save.get(subx[i]+1,n<<1)<<'\n';
        ans=max(ans,dpfor[i]+save.get(subx[i]+1,n<<1));
        save.update(a[i],dpback[i]);
    }
    cout<<ans;
    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 13 / 13
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 17 / 17
• Subtask 7: 25 / 25