Submission #296079

#	Time	Username	Problem	Language	Result	Execution time	Memory
296079		RealSuperman1	Roller Coaster Railroad (IOI16_railroad)	C++14	34 / 100	224 ms	26232 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.se > y.se;
}

ll case3(vector <int> s, vector <int> t) {
	vector <pii> s1(n);
	vector <int> pos(n), l(n);
	for (int i = 0; i < n; i++)
		s1[i] = {s[i], i};
	sort(s1.begin(), s1.end());
	for (int i = 0; i < n; i++)
		pos[s1[i].se] = i;
//	for (auto to : s1)
//		cout << to.fi << " " << to.se << endl;
//	cout << endl;
	for (int i = 0; i < n; i++) {
		int L, R, M;
		L = 0; R = n - 1;
		l[i] = n;
		while (L <= R) {
			M = (L + R) / 2;
			if (s1[M].fi >= t[i]) {
				l[i] = min(l[i], M);
				R = M - 1;	
			} else
				L = M + 1;
		}
//		cout << i << " " << t[i] << " " << l[i] << endl;
	}
//	return 0;
	vector < vector <pii> > lhere(n);
	for (int i = 0; i < n; i++)
		if (l[i] < n)
			lhere[l[i]].pb({i, pos[i]});
	for (int i = 0; i < n; i++)
		sort(lhere[i].begin(), lhere[i].end(), cmp);
	set <int> notvis = {};
	for (int i = 0; i < n; i++)
		notvis.insert(i);
	vector <int> nx(n, -1);
	set <int>::iterator it;
	for (int i = 0; i < n; i++) {
		for (auto to : lhere[i]) {
//			cout << "Cur " << to.fi << " " << to.se << endl;
			int u = to.fi, p = to.se;
			it = notvis.lower_bound(i);
			if (it == notvis.end())
				continue;
			int val = *it;
			if (s1[val].se == u) {
				it = notvis.lower_bound(val + 1);
			}
			if (it == notvis.end())
				continue;
			val = *it;
			nx[u] = s1[val].se;
			notvis.erase(val);
		}
	}
	if (notvis.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 case3(std::vector<int>, std::vector<int>)':
railroad.cpp:60:19: warning: unused variable 'p' [-Wunused-variable]
   60 |    int u = to.fi, p = to.se;
      |                   ^
railroad.cpp: In function 'long long int plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:114:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  114 |   for (int i = 0; i < b.size(); i++)
      |                   ~~^~~~~~~~~~
railroad.cpp:115:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  115 |    for (int j = 0; j < b.size(); j++) {
      |                    ~~^~~~~~~~~~

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