Submission #557105

#	Time	Username	Problem	Language	Result	Execution time	Memory
557105		fuad27	Aliens (IOI16_aliens)	C++17	60 / 100	2059 ms	11800 KiB

aliens

#include<bits/stdc++.h>
#include "aliens.h"
using namespace std;
using ll = long long;
const ll inf = 2e18;
struct Line {
	mutable ll k, m, p;
	bool operator<(const Line& o) const { return k < o.k; }
	bool operator<(ll x) const { return p < x; }
};

struct LineContainer : multiset<Line, less<>> {
	// (for doubles, use inf = 1/.0, div(a,b) = a/b)
	static const ll inf = LLONG_MAX;
	ll div(ll a, ll b) { // floored division
		return a / b - ((a ^ b) < 0 && a % b); }
	bool isect(iterator x, iterator y) {
		if (y == end()) return x->p = inf, 0;
		if (x->k == y->k) x->p = x->m > y->m ? inf : -inf;
		else x->p = div(y->m - x->m, x->k - y->k);
		return x->p >= y->p;
	}
	void add(ll k, ll m) {
		auto z = insert({k, m, 0}), y = z++, x = y;
		while (isect(y, z)) z = erase(z);
		if (x != begin() && isect(--x, y)) isect(x, y = erase(y));
		while ((y = x) != begin() && (--x)->p >= y->p)
			isect(x, erase(y));
	}
	ll query(ll x) {
		assert(!empty());
		auto l = *lower_bound(x);
		return l.k * x + l.m;
	}
};
LineContainer cht;
void ins(ll k, ll m) {
	cht.add(-k, -m);
}
ll que(ll x) {
	return -cht.query(x);
}
long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c) {
	for(int i = 0;i<n;i++) {
		if(r[i] > c[i]) {
			swap(r[i], c[i]);
		}
	}
	vector<pair<long long,long long>> v;
	{
		vector<pair<long long, long long>> d;
		for(int i = 0;i<n;i++)d.push_back(make_pair(r[i], -c[i]-1));
		sort(d.begin(), d.end());
		for(int i = 0;i<n;i++)d[i].second*=-1;
		long long mxr = -inf;
		for(int i = 0; i<n; i++) {
			if(d[i].second > mxr) {
				v.push_back(make_pair(d[i].second, d[i].first));
				mxr = d[i].second;
			}
		}
	}
	sort(v.begin(), v.end());
	n = v.size();
	vector<long long> dp[2];
	for(int i = 0;i<2;i++)dp[i].resize(n+1);
	for(int i = 0;i<=n;i++)dp[0][i] = inf;
	dp[0][0] = 0;
	for(int p = 1;p<=k;p++) {
		int j = 1;
		cht.clear();
		for(int i = 1;i<=n;i++) {
			dp[j][i] = inf;
			long long f = -2*v[i-1].second;
			long long s = v[i-1].second*v[i-1].second+dp[j-1][i-1];
			if(i!=1 and v[i-2].first > v[i-1].second) {
				s-=(v[i-2].first-v[i-1].second)*(v[i-2].first-v[i-1].second);
			}
			ins(f, s);
			dp[j][i] = que(v[i-1].first) + v[i-1].first*v[i-1].first;
		}
		swap(dp[1], dp[0]);
	}
	return dp[0][n];
}

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