Submission #477619

#	Time	Username	Problem	Language	Result	Execution time	Memory
477619		JovanB	Aliens (IOI16_aliens)	C++17	60 / 100	2093 ms	6876 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;

const ll INF = 1000000000000000000LL;
const int N = 1000000;

struct line{
    ll k, n;
    ll eval(ll x){ return k*x + n; }
    ld intersect(line g){
        return 1.0*(n - g.n)/(g.k - k);
    }
} seg[4*N+5];

ll dp[N+5];

ll presek(pair <ll, ll> a, pair <ll, ll> b){
    ll h = max(0LL, a.second - b.first + 1);
    return h*h;
}

void dodaj(deque <line> &q, line k){
    while(q.size() > 1){
        line g = q.back();
        q.pop_back();
        ld x1 = q.back().intersect(g);
        ld x2 = g.intersect(k);
        if(x1 < x2){
            q.push_back(g);
            break;
        }
    }
    q.push_back(k);
}

ll query(deque <line> &q, ll x){
    while(q.size() > 1 && q[0].eval(x) >= q[1].eval(x)) q.pop_front();
    return q.front().eval(x);
}

long long take_photos(int n, int m, int k, std::vector<int> _r, std::vector<int> _c) {
    vector <pair <int, int>> points;
    for(int i=0; i<n; i++){
        if(_r[i] > _c[i]) swap(_r[i], _c[i]);
        points.push_back({_r[i] + 1, _c[i] + 1});
    }
    sort(points.begin(), points.end(), [](pair <int, int> a, pair <int, int> b){ if(a.second == b.second) return a.first < b.first; return a.second > b.second; });
    vector <pair <ll, ll>> vec;
    for(auto c : points){
        if(vec.empty() || c.first < vec.back().first) vec.push_back(c);
    }
    reverse(vec.begin(), vec.end());
    n = vec.size();
    ll res = INF;
    for(int turns=1; turns<=k; turns++){
        deque <line> q;
        if(turns == 1) dodaj(q, {-2*(vec[0].first - 1), vec[0].first*vec[0].first - 2*vec[0].first});
        for(int i=0; i<n; i++){
            ll g = dp[i];
            dp[i] = 1 + vec[i].second*vec[i].second + query(q, vec[i].second);
            if(i != n-1 && turns != 1) dodaj(q, {-2*(vec[i+1].first - 1), vec[i+1].first*vec[i+1].first - 2*vec[i+1].first - presek(vec[i], vec[i+1]) + g});
        }
        res = min(res, dp[n-1]);
        while(!q.empty()) q.pop_back();
    }
    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