Submission #429139

#	Time	Username	Problem	Language	Result	Execution time	Memory
429139		JeanBombeur	Aliens (IOI16_aliens)	C++17	4 / 100	11 ms	7672 KiB

aliens

#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include "aliens.h"
using namespace std;

//    <|°_°|>

const long long INFINI = (1LL << 60);
const int MAX_POINTS = (4001);
const int LOG = (40);

struct droite {
    long long pente, cst;
    int prix;
};

long long DP[MAX_POINTS][MAX_POINTS];

pair <long long, long long> Points[MAX_POINTS];
pair <int, int> Aliens[MAX_POINTS];

droite Deque[MAX_POINTS][MAX_POINTS];
int deb[MAX_POINTS];
int fin[MAX_POINTS];

int nbPoints = 0;

bool Compare(pair <int, int> a, pair <int, int> b) {
    if (a.first != b.first)
        return a.first < b.first;
    return a.second > b.second;
}

long long Inter(droite a, droite b) {
    if (a.pente == b.pente)
        return INFINI;
    if (a.pente < b.pente)
        swap(a, b);
    return (b.cst - a.cst + a.pente - b.pente - 1) / (a.pente - b.pente);
}

void Insert(droite a, int id) {
    while (fin[id] > deb[id] + 1 && Inter(Deque[fin[id] - 2][id], a) <= Inter(Deque[fin[id] - 2][id], Deque[fin[id] - 1][id]))
        fin[id] --;
    Deque[fin[id] ++][id] = a;
    return;
}

pair <long long, int> GetMin(long long absc, int id) {
    while (fin[id] > deb[id] + 1 && absc >= Inter(Deque[deb[id]][id], Deque[deb[id] + 1][id]))
        deb[id] ++;
    return {Deque[deb[id]][id].pente * absc + Deque[deb[id]][id].cst, Deque[deb[id]][id].prix};
}

// pair <long long, int> FindDP(long long lambda) {
//     deb = 0, fin = 0;
//     pair <long long, int> DP = {0LL, 0};
//     Insert({- 2 * Points[0].first, Points[0].first * Points[0].first, 0});
//     for (int i = 0; i < nbPoints; i ++)
//     {
//         DP = GetMin(Points[i].second);
//         DP.first += Points[i].second * Points[i].second + lambda;
//         DP.second ++;
//         if (i + 1 < nbPoints)
//         {
//             long long d = max(0LL, Points[i].second - Points[i + 1].first);
//             Insert({- 2 * Points[i + 1].first,
//             Points[i + 1].first * Points[i + 1].first - d * d + DP.first, DP.second});
//         }
//     }
//     return DP;
// }

void Treat(int noeud) {
    for (int i = 1; i <= nbPoints; i ++)
    {
        DP[noeud][i] = GetMin(Points[noeud].second, i - 1).first + Points[noeud].second * Points[noeud].second;
    }
    if (noeud + 1 == nbPoints)
        return;
    for (int i = 1; i <= nbPoints; i ++)
    {
        long long d = max(0LL, Points[noeud].second - Points[noeud + 1].first);
        Insert({- 2 * Points[noeud + 1].first, Points[noeud + 1].first * Points[noeud + 1].first - d * d + DP[noeud][i], 0}, i);
    }
    return;
}

void DPDebile() {
    Insert({- 2 * Points[0].first, Points[0].first * Points[0].first, 0}, 0);
    for (int i = 0; i < nbPoints; i ++)
    {
        Treat(i);
    }
    return;
}

long long take_photos(int nbAliens, int tailleMax, int nbPhotos, vector<int> Lignes, vector<int> Colonnes) {
    
    tailleMax ++;
    
    for (int i = 0; i < nbAliens; i ++)
    {
        if (Lignes[i] > Colonnes[i])
            swap(Lignes[i], Colonnes[i]);
        Aliens[i] = {Lignes[i], Colonnes[i] + 1};
    }
    sort(Aliens, Aliens + nbAliens, Compare);
    
    for (int i = 0; i < nbAliens; i ++)
    {
        if (nbPoints == 0 || Aliens[i].second > (int)Points[nbPoints - 1].second)
            Points[nbPoints ++] = Aliens[i];
    }
    
    DPDebile();
    
    return DP[nbPoints - 1][min(nbPhotos, nbPoints)];
    /*
    long long lambda = -1;
    long long ans = 0;
    for (long long i = (1LL << LOG); i > 0; i /= 2)
    {
        pair <long long, int> DP = FindDP(lambda + i);
        if (DP.second <= nbPhotos)
            ans = DP.first - (lambda + i) * DP.second;
        else
            lambda += i;
    }
    return ans;*/
}

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