Submission #59702

#	Time	Username	Problem	Language	Result	Execution time	Memory
59702		KieranHorgan	Aliens (IOI16_aliens)	C++17	41 / 100	2063 ms	125684 KiB

aliens

#pragma GCC optimize("Ofast")
#include "aliens.h"
#include <bits/stdc++.h>
using namespace std;
 
#define int long long
 
vector<pair<int, int>> intervals;
int cost(int i, int l) {
	int overlap = max(0ll, intervals[l].second-intervals[l+1].first+1);
	return (intervals[i].second-intervals[l+1].first+1)*(intervals[i].second-intervals[l+1].first+1) - overlap*overlap;
}
 
long long take_photos(signed n, signed m, signed k, vector<signed> r, vector<signed> c) {
	// r.clear();
	// c.clear();
	// srand(4);
	// n = 100;
	// k = 8;
	// m = 1000;
	for(int i = 0; i < n; i++) {
		r.push_back(rand()%m);
		c.push_back(rand()%m);
		if(c[i] >= r[i])
			intervals.push_back({r[i], -c[i]});
		else
			intervals.push_back({c[i], -r[i]});
	}
	sort(intervals.begin(), intervals.end());
 
	auto interStore = intervals;
	intervals.clear();
	intervals.push_back({-1, -1});
	int ma = -1;
	for(auto p: interStore) {
		if(-p.second > ma) {
			ma = -p.second;
			intervals.push_back({p.first, -p.second});
			// cerr << p.first << "->" << -p.second << endl;
		}
	}
 
 
	n = intervals.size()-1;
	k = min(k, n);
 
	vector<vector<int>> dp(k+1, vector<int>(n+1, 1ll<<60));
	vector<vector<int>> opt(k+1, vector<int>(n+1, 0));
	dp[0][0] = 0;
	for(int j = 1; j <= k; j++) {
		for(int i = j; i <= n; i++) {
			// cerr << j << " " << i << ": ";
			for(int l = max(opt[j][i-1], opt[j-1][i]); l < (j==1?1:i); l++) {
				if(dp[j-1][l] + cost(i, l) < dp[j][i]) {
					opt[j][i] = l;
					dp[j][i] = dp[j-1][l] + cost(i, l);
				}
			}
			// cerr << endl;
		}
	}
 
    return dp[k][n];
}

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