Submission #260009

#	Time	Username	Problem	Language	Result	Execution time	Memory
260009		ant101	Roller Coaster Railroad (IOI16_railroad)	C++14	41 / 100	527 ms	61216 KiB

railroad

#include "railroad.h"
#include <iostream>
#include <vector>
#include <algorithm>
#include <random>
#include <set>
#include <map>
#include <queue>
#include <cstring>
#include <cmath>
#include <bitset>
#include <iomanip>
#include <functional>
 
using namespace std;
 
template<typename T> void uin(T &a, T b) {
	if (b < a) a = b;
}
 
#define all(v) v.begin(), v.end()
 
const long long INF = 1e18 + 228;
const int OGO = 1000 * 1000 * 1000 + 228;
const int N = 400 * 1000 + 228;
 
long long dp[(1 << 17) + 17][16];
 
vector<int> crd;
vector<int> g[N], gr[N];
 
int pref[N];
bool used[N];
 
 
void dfs(int v) {
	used[v] = 1;
	for (int to : gr[v]) {
		if (!used[to]) {
			dfs(to);
		}
	}
}
 
int Get(int i) {
	return lower_bound(all(crd), i) - crd.begin() + 1;
}
 
void AddEdge(int from, int to) {
	from = Get(from);
	to = Get(to);
	g[from].emplace_back(to);
	++pref[from];
	--pref[to];
	gr[from].emplace_back(to);
	gr[to].emplace_back(from);
}
 
long long plan_roller_coaster(vector<int> s, vector<int> t) {
    int n = (int)s.size();
	if (n <= 15) {
		for (int i = 0; i < (1 << n); ++i) {
			for (int j = 0; j < n; ++j) {
				dp[i][j] = INF;
			}
		}
		for (int fir = 0; fir < n; ++fir) {
			dp[1 << fir][fir] = 0;
		}
		for (int mask = 0; mask < (1 << n); ++mask) {
			for (int last = 0; last < n; ++last) {
				if (dp[mask][last] != INF) {
					for (int new_last = 0; new_last < n; ++new_last) {
						if ((mask >> new_last) & 1) continue;
						long long cur = dp[mask][last] + max(0, t[last] - s[new_last]);
						uin(dp[mask | (1 << new_last)][new_last], cur);
					}
				}
			}
		}
		long long answer = INF;
		for (int last = 0; last < n; ++last) {
			uin(answer, dp[(1 << n) - 1][last]);
		}
		return answer;
	} else {
		// subtask 3
		crd.clear();
		for (int i = 0; i < n; ++i) {
			crd.emplace_back(s[i]);
			crd.emplace_back(t[i]);
		}
		crd.emplace_back(OGO);
		sort(crd.begin(), crd.end());
		crd.erase(unique(crd.begin(), crd.end()), crd.end());
		int sz = (int)crd.size();
		for (int i = 0; i < n; ++i) {
			AddEdge(s[i], t[i]);
		}
		AddEdge(OGO, 1);
		for (int i = 1; i < sz; ++i) {
			pref[i] += pref[i - 1];
			if (pref[i] > 0) {
				return 10;
			}
			if (pref[i] != 0) {
				gr[i].emplace_back(i + 1);
				gr[i + 1].emplace_back(i);
			}
		}
		int comps = 0;
		for (int i = 1; i <= sz; ++i) {
			if (!used[i]) {
				dfs(i);
				++comps;
			}
		}
		if (comps > 1) {
			return 20;
		} else {
			return 0;
		}
 
	}
    return 0;
}

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