Submission #1193399

#	Time	Username	Problem	Language	Result	Execution time	Memory
1193399		simona1230	Aliens (IOI16_aliens)	C++20	4 / 100	1 ms	328 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>
using namespace std;

struct line
{
    long long a,b,id;
    line() {}
    line(long long _a,long long _b,int _id)
    {
        a=_a;
        b=_b;
        id=_id;
    }
    long long data(long long x)
    {
        return a*x+b;
    }
};

deque<line> cht,cht2;

int num;
pair<int,int> p[200001];
bool cmp(pair<int,int> p1,pair<int,int> p2)
{
    if(p1.second==p2.second)return p1.first<p2.first;
    return p1.second<p2.second;
}

long long sq(long long x)
{
    return x*x;
}

double pt(line l1,line l2)
{
    return (double)(l2.b-l1.b)/(double)(l1.a-l2.a);
}

void insert_(line l)
{
    //cout<<l.a<<" - "<<l.b<<endl;
    while(cht.size()>=2&&pt(cht[cht.size()-1],l)<pt(cht[cht.size()-2],l))cht.pop_back();
    cht.push_back(l);
}

int s;
long long value(long long x,int id)
{
    s=min(s,(int)cht.size()-1);
    int h=s;
    long long ans=1e18;
    for(int i=s; i<cht.size(); i++)
        if(cht[i].id<id)
        {
            //cout<<cht[i].data(x)<<" ";
            ans=min(ans,cht[i].data(x));
            if(ans==cht[i].data(x))h=i;
            else break;
        }
        else break;
    s=h;
    //cout<<endl;
    return ans;
}

long long dp[200001];
int cnt[200001];
void compute(long long c)
{
    cht.clear();
    dp[0]=sq(p[0].second-p[0].first+1)+c;
    cnt[0]=1;

    long long b=-2*p[1].first+dp[0]-sq(max(0,p[0].second-p[1].first+1))+sq(p[1].first);
    insert_({-2*p[1].first,b,0});

    s=0;
    //cout<<"! "<<c<<" !!!"<<endl;
    for(int i=1; i<num; i++)
    {
        dp[i]=sq(p[i].second+1)+value(p[i].second,i)+c;
        //cout<<". "<<dp[i]<<endl;
        cnt[i]=cnt[s]+1;

        if(dp[i]>sq(p[i].second-p[0].first+1)+c)
        {
            dp[i]=sq(p[i].second-p[0].first+1)+c;
            //cout<<"? "<<dp[i]<<endl;
            cnt[i]=1;

            b=-2*p[i+1].first+dp[i]-sq(max(0,p[i].second-p[i+1].first+1))+sq(p[i+1].first);
            insert_({-2*p[i+1].first,b,i});

            continue;
        }

        b=-2*p[i+1].first+dp[i]-sq(max(0,p[i].second-p[i+1].first+1))+sq(p[i+1].first);
        insert_({-2*p[i+1].first,b,i});
    }

    //for(int i=0;i<num;i++)
    //    cout<<dp[i]<<" "<<cnt[i]<<endl;
}

long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c)
{
    for(int i=0; i<n; i++)
        p[i]= {min(r[i],c[i]),max(r[i],c[i])};
    sort(p,p+n,cmp);
    for(int i=0; i<n; i++)
    {
        if(i!=0&&p[i].second==p[i-1].second)continue;
        while(num!=0&&p[num-1].first>=p[i].first)num--;
        p[num++]=p[i];
    }

    long long ans=1e18;

    long long lf=0,rt=1e12;
    long long x=0;
    while(1)
    {
        //long long x=(lf+rt)/2;
        compute(x);
        if(cnt[num-1]<=k)
        {
            rt=x-1;
            ans=min(ans,dp[num-1]-cnt[num-1]*x);
            break;
        }
        x++;
        //else break;
    }

    return ans;
}

Compilation message (stderr)

aliens.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
aliens_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

• Subtask 1: 4 / 4
• Subtask 2: 0 / 12
• Subtask 3: 0 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40