Submission #1273994

#	Time	Username	Problem	Language	Result	Execution time	Memory
1273994		coderg300711	Aliens (IOI16_aliens)	C++20	4 / 100	2 ms	348 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(x) (x).begin(), (x).end()
#define sz(x) int(x.size())

ll pow2(ll v) {
    return v*v;
}

struct Line{
    ll a, b;
    ll eval(ll x) {
        return a * x + b;
    }
};

struct CHT {

    deque<Line> deq;

    void add(Line line) {
        if (not deq.empty() and deq.front().a == line.a) {
            if (deq.front().b < line.b) {
                return;
            } else {
                deq.pop_front();
            }
        }
        while (sz(deq) >= 2) {
            if ((deq[0].a - line.a) * (deq[1].b - deq[0].b) >= (deq[0].b - line.b) * (deq[1].a - deq[0].a)) {
                deq.pop_front();
            } else {
                break;
            }
        }
        deq.push_front(line);
    }

    ll query(ll x) {
        while (sz(deq) >= 2) {
            if (deq[sz(deq) - 1].eval(x) >= deq[sz(deq) - 2].eval(x)) {
                deq.pop_back();
            } else break;
        }
        return deq.back().eval(x);
    }
};

long long take_photos(int n, int m, int K, vector<int> r, vector<int> c) {
    vector<pair<int, int>> pts(n);
    for(int i=0;i<n;i++){
        if (r[i] > c[i]) {
            swap(r[i], c[i]);
        }
        pts[i] = make_pair(r[i], c[i]);
    }
    sort(all(pts));
    {
        vector<pair<int, int>> pts2;
        for(int i=0;i<n;i++){
            if (i != n - 1 and pts[i].first == pts[i + 1].first) {
                continue;
            }
            pts2.push_back(pts[i]);
        }
        pts = pts2;
        n = sz(pts);
    }
    {
        vector<pair<int, int>> pts2;
        int mx_c = -1;
        for(int i=0;i<n;i++){
            if (pts[i].second <= mx_c) {
                continue;
            }
            pts2.push_back(pts[i]);
            mx_c = max(mx_c, pts[i].second);
        }
        pts = pts2;
        n = sz(pts);
    }

    vector<vector<ll>> dp(n+1,vector<ll>(K+1,1LL<<60));
    dp[0][0]=0;
    for(int k=0;k<K;k++){
        CHT cht;
        for(int i=0;i<=n;i++){
            if (i != 0) {
                ll x = pts[i - 1].second;
                ll mn = cht.query(x);
                ll res = mn + x * x;
                dp[i][k + 1] = res;
            }
            if (i==n)continue;
            ll a = 2 * (-pts[i].first + 1);
            ll diff = pow2(max(0ll, i == 0 ? 0ll : (pts[i - 1].second - pts[i].first + 1)));
            ll b = dp[i][k] + pow2(-pts[i].first + 1) - diff;
            cht.add({a, b});
        }
    }
    ll ans=1LL<<60;
    for(int i=0;i<=K;i++)ans=min(ans,dp[n][i]);

    return ans;
}

Compilation message (stderr)

aliens.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
aliens_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

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