Submission #890565

#	Time	Username	Problem	Language	Result	Execution time	Memory
890565		ASN49K	Aliens (IOI16_aliens)	C++14	0 / 100	1 ms	348 KiB

aliens

#include <bits/stdc++.h>
#include "aliens.h"
using namespace std;
using i64=long long;
const i64 INF=1e18;
#define bug(x) cerr<<#x<<x<<'\n';
#define all(yy) yy.begin(),yy.end()
#define pb push_back
const int inf=1e9;
struct duo
{
    int l,r;
    bool operator <(const duo&b)const
    {
        if(l==b.l)
        {
            return r>b.r;
        }
        return l<b.l;
    }
};
////////////////////////////GEOMETRY
////////////////////////////////////
struct line
{
    i64 a,b;
    i64 calculate(int x)
    {
        return a*x+b;
    }
};
struct node
{
    line a;
    int k;
};
i64 intersect(const line& c,const line& d)
{
    assert(c.a!=d.a);
    return (d.b-c.b+c.a-d.a-1)/(c.a-d.a);
}
struct CHT
{
    deque<node>d;
    void add(const node e)
    {
        while(d.size()>=2)
        {
            i64 i1=intersect(d[d.size()-2].a,d.back().a);
            i64 i2=intersect(d.back().a,e.a);
            if(i1>i2)
            {
                d.pop_back();
            }
            else
            {
                break;
            }
        }
        d.pb(e);
    }
    pair<i64,int> query(int val)
    {
        while(d.size()>=2 && d[0].a.calculate(val)>=d[1].a.calculate(val))
        {
            d.pop_front();
        }
        return {d[0].a.calculate(val),d[0].k};
    }
    void clear()
    {
        d.clear();
    }
};
i64 pow2(i64 x)
{
    return x*x;
}
/////////////////////////////////////////////////////
/////////////////////////////////////////////////////
pair<i64,int> aliens(vector<duo>&a,int n,i64 cost_extra)
{
    CHT cht;
    cht.add({{-2*(a[0].l-1),pow2(a[0].l-1)},0});
    pair<i64,int>sol;
    for(int i=0;i<n;i++)
    {
        sol=cht.query(a[i].r);
        sol.first+=pow2(a[i].r)+cost_extra;
        sol.second++;
        cht.add({{-2*(a[i+1].l-1) , pow2(a[i+1].l-1)-pow2(max(0,a[i].r-a[i+1].l+1))+sol.first},sol.second});
    }
    return sol;
}
i64 take_photos(int n, int m, int k, vector<int> rr, vector<int> cc)
{
    vector<duo>a(n);
    for(int i=0;i<n;i++)
    {
        a[i]={min(rr[i],cc[i]),max(rr[i],cc[i])};
    }
    vector<duo>aux=a;
    a.clear();
    sort(all(aux));
    int maxx=-1;
    for(auto &c:aux)
    {
        if(c.r>maxx)
        {
            a.pb(c);
            maxx=c.r;
        }
    }
    aux.clear();
    assert(n!=a.size());
    n=(int)a.size();
    i64 st=0,dr=1LL*m*m;
    i64 rez=INF;
    for(int i=0;i<=dr;i++)
    {
        auto sol=aliens(a,n,i);
        if(sol.second<=k)
        {
            rez=min(rez,sol.first-i*sol.second);
        }
    }
    return rez;
}

Compilation message (stderr)

In file included from /usr/include/c++/10/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:33,
                 from aliens.cpp:1:
aliens.cpp: In function 'i64 take_photos(int, int, int, std::vector<int>, std::vector<int>)':
aliens.cpp:115:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<duo>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  115 |     assert(n!=a.size());
      |            ~^~~~~~~~~~
aliens.cpp:117:9: warning: unused variable 'st' [-Wunused-variable]
  117 |     i64 st=0,dr=1LL*m*m;
      |         ^~

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