Submission #892013

#	Time	Username	Problem	Language	Result	Execution time	Memory
892013		ASN49K	Aliens (IOI16_aliens)	C++14	100 / 100	123 ms	6052 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;
};
#define db long double
struct ConvexHull_Trick
{
    struct Line { i64 a,b; int cnt; } st[100005];
    int top,j;
    void Init() { top=0; j=1; }
    db intersect(Line x,Line y)
    {
        return (db)(y.b-x.b) / (db)(x.a-y.a);
    }
    void add(i64 a,i64 b,int cnt)
    {
        while(top>1)
        {
            db y1=intersect({ a,b },st[top-1]),y2=intersect(st[top],st[top-1]);
            if(y1<y2 || (y1==y2 && st[top].cnt<cnt)) top--;
            else break;
        }
        if(top>0) j=min(j,top);
        else j=1;
        st[++top]={ a,b,cnt };
    }
    pair<i64,int> get(i64 x)
    {
        while(j<top)
        {
            i64 y1=x*st[j].a+st[j].b,y2=x*st[j+1].a+st[j+1].b;
            if(y1>y2 || (y1==y2 && st[j].cnt<st[j+1].cnt)) j++;
            else break;
        }
        return { x*st[j].a+st[j].b,st[j].cnt };
    }
}cht;
 
i64 pow2(i64 x)
{
    return x*x;
}
/////////////////////////////////////////////////////
/////////////////////////////////////////////////////
pair<i64,int> aliens(vector<duo>&a,int n,i64 cost_extra)
{
    cht.Init();
    cht.add(-2*(a[0].l-1),pow2(a[0].l-1),0);
    pair<i64,int>sol={-1,-1};
    for(int i=0;i<n;i++)
    {
        sol=cht.get(a[i].r);
        sol.first+=pow2(a[i].r)+cost_extra;
        sol.second++;
        if(i!=n-1)
        {
            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;
}
long long 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();
    n=(int)a.size();
    k=min(n,k);
    long long st=0,dr=1e12;
    long long rez=aliens(a,n,0).first;
    while(st<=dr)
    {
        long long m=(st+dr)/2;
        auto sol=aliens(a,n,m);
        if(k>=sol.second)
        {
            dr=m-1;
        }
        else
        {
            st=m+1;
            rez=sol.first-k*m;
        }
    }
    return rez;
}

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