Submission #296115

#	Time	Username	Problem	Language	Result	Execution time	Memory
296115		RealSuperman1	Roller Coaster Railroad (IOI16_railroad)	C++14	64 / 100	260 ms	20092 KiB

railroad

#include "railroad.h"
#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define fi first
#define se second
#define pll pair<long long, long long>
#define pii pair<int, int>

using namespace std;

const ll INF = 1e18;

int n;

bool cmp(pii x, pii y) {
	return x.fi > y.fi;
}

ll case3(vector <int> s, vector <int> t) {
	vector <pii> t1(n);
	for (int i = 0; i < n; i++)
		t1[i] = {t[i], i};
	sort(t1.begin(), t1.end(), cmp);
//	for (auto to : s1)
//		cout << to.fi << " " << to.se << endl;
//	cout << endl;
//	return 0;
	set <pii> sn = {};
	for (int i = 0; i < n; i++)
		sn.insert({s[i], i});
	set <pii>::iterator it;
	for (int i = 0; i < n; i++) {
		it = sn.lower_bound({t1[i].fi, 0});
		if (it == sn.end())
			continue;
		pii val = *it;
		if (val.se == t1[i].se)
			it = sn.upper_bound(val);
		if (it == sn.end())
			continue;
		val = *it;
//		cout << t1[i].se << "->" << val.se << endl;
		sn.erase(it);
	}
	if (sn.size() <= 1)
		return 0;
	return 1;
}

ll plan_roller_coaster(vector <int> s, vector <int> t) {
	n = s.size();
	if (n > 16) {
		return case3(s, t);
	}
	vector < vector <ll> > w;
	vector < vector <ll> > dp;
	w.resize(n);
	for (int i = 0; i < n; i++) {
		w[i].resize(n);
		for (int j = 0; j < n; j++) {
			if (i == j)
				continue;
			w[i][j] = max(0, t[i] - s[j]); 
		}
	}
	dp.resize((1 << n));
	for (int mask = 0; mask < (1 << n); mask++) {
		dp[mask].resize(n);
		for (int i = 0; i < n; i++)
			dp[mask][i] = INF;
	}
	for (int i = 0; i < n; i++)
		dp[0][i] = 0;
	vector <int> b;
	for (int mask = 1; mask < (1 << n); mask++) {
		b.clear();
		for (int i = 0; i < n; i++)
			if (1 & (mask >> i))
				b.pb(i);
		if (b.size() == 1) {
			dp[mask][b[0]] = 0;
			continue;
		}
		for (int i = 0; i < b.size(); i++)
			for (int j = 0; j < b.size(); j++) {
				if (i == j)
					continue;
				int mask1 = (mask ^ (1 << b[i]));
				dp[mask][b[i]] = min(dp[mask][b[i]], dp[mask1][b[j]] + w[b[j]][b[i]]);
			}
	}
	ll ans = INF;
	for (int i = 0; i < n; i++)
		ans = min(ans, dp[(1 << n) - 1][i]);
	return ans;
}

Compilation message (stderr)

railroad.cpp: In function 'long long int plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:85:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |   for (int i = 0; i < b.size(); i++)
      |                   ~~^~~~~~~~~~
railroad.cpp:86:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   86 |    for (int j = 0; j < b.size(); j++) {
      |                    ~~^~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 30 / 30
• Subtask 4: 0 / 36