Submission #764692

#	Time	Username	Problem	Language	Result	Execution time	Memory
764692		Valters07	Aliens (IOI16_aliens)	C++14	60 / 100	2081 ms	10152 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;
};
vector<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)
{
    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});
            return;
        }
        hull.pop_back();
    }
    hull.pb({-2e18,a,b});
}
ll getmax(ll x)
{
    auto t = *--upper_bound(hull.begin(),hull.end(),x,[](ll x, node t){return (x<t.x);});
    return (ll)getval(x,t.a,t.b);
}
ll take_photos(int n, int m, int k, vector<int> r, vector<int> c)
{
    vector<pair<int,int> > seg(n);
    for(int i = 0;i<n;i++)
    {
        if(r[i]>c[i])
            swap(r[i],c[i]);
        seg[i]={r[i]+1,c[i]+1};
    }
    clean(seg);
    n=seg.size();
    k=min(k,n);
    ll coll[n];
    coll[0]=0;
    for(int i = 1,t;i<n;i++)
        t=max(0,seg[i-1].se-seg[i].fi+1),
        coll[i]=1ll*t*t;
    vector<ll> dp(n+1), dp1(n+1);
    for(int i = 0,t;i<n;i++)
        t=seg[i].se-seg[0].fi+1,
        dp[i+1]=1ll*t*t;
    ll res = dp[n];
    for(int j = 2;j<=k;j++)
    {
        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));
            dp1[i+1]=getmax(r)+r*(r+2)+1;
        }
        swap(dp,dp1);
        hull.clear();
        res=min(res,dp[n]);
    }
    return res;
}

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