Submission #767956

#	Time	Username	Problem	Language	Result	Execution time	Memory
767956		Valters07	Aliens (IOI16_aliens)	C++14	100 / 100	243 ms	8620 KiB

aliens

#include <bits/stdc++.h>
#include "aliens.h"
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")
#define fio ios_base::sync_with_stdio(0);cin.tie(0);
#define ll long long
#define en cin.close();return 0;
#define pb push_back
#define fi first//printf("%lli\n",cur);
#define se second//scanf("%lli",&n);
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
struct node
{
    long double x;
    ll a, b, k;//implemento sito pasu, bet ar k
};
deque<node> hull;
void clean(vector<pair<int,int> > &seg)
{
    sort(seg.begin(),seg.end(),[](auto &i, auto &j)
    {
        if(i.fi==j.fi)
            return (i.se>j.se);
        return (i.fi<j.fi);
    });
    vector<pair<int,int> > tmp;
    int r = 0;
    for(auto x:seg)
    {
        if(x.se>r)
            tmp.pb(x);
        r=max(r,x.se);
    }
    swap(seg,tmp);
}
long double getval(long double x, ll a, ll b)
{
    return x*a+b;
}
long double inters(ll a1, ll b1, ll a2, ll b2)
{
    return (long double)(b1-b2)/(a2-a1);
}
void addline(ll a, ll b, ll k)
{
    while(!hull.empty())
    {
        auto t = hull.back();
        if(getval(t.x,a,b)>getval(t.x,t.a,t.b))
        {
            if(t.a-a)
                hull.pb({inters(t.a,t.b,a,b),a,b,k});
            return;
        }
        hull.pop_back();
    }
    hull.pb({-2e18,a,b,k});
}
pair<ll,int> getmax(ll x)
{
    while(hull.size()>1&&hull[1].x<=x&&!(hull[1].x==x&&hull[0].k<hull[1].k))
        hull.pop_front();
    auto t = hull[0];
    return {(ll)getval(x,t.a,t.b),t.k};
}
pair<ll,int> godp(vector<pair<int,int> > &seg, ll c, vector<ll> &coll)
{
    int n = seg.size();
    vector<ll> dp(n+1), kc(n+1);
    for(int i = 0;i<n;i++)
    {
        ll l = seg[i].fi, r = seg[i].se;
        addline(-2*l,dp[i]-coll[i]+l*(l-2),kc[i]+1);
        auto t = getmax(r);
        dp[i+1]=t.fi+r*(r+2)+1+c;
        kc[i+1]=t.se;
    }
    return {dp[n],kc[n]};
}
ll take_photos(int n, int m, int k, vector<int> row, vector<int> col)
{
    vector<pair<int,int> > seg(n);
    for(int i = 0;i<n;i++)
    {
        if(row[i]>col[i])
            swap(row[i],col[i]);
        seg[i]={row[i]+1,col[i]+1};
    }
    clean(seg);
    n=seg.size();
    k=min(k,n);
    vector<ll> coll(n);
    for(int i = 1,t;i<n;i++)
        t=max(0,seg[i-1].se-seg[i].fi+1),
        coll[i]=1ll*t*t;
    ll l = 0, r = 1ll*m*m;
    while(l<r)
    {
        ll mid = (l+r)/2;
        auto t = godp(seg,mid,coll);
        if(t.se>k)
            l=mid+1;
        else
            r=mid;
        hull.clear();
    }
    auto t = godp(seg,l,coll);
    return t.fi-k*l;
}

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