Submission #390984

#	Time	Username	Problem	Language	Result	Execution time	Memory
390984		SuhaibSawalha1	Sky Walking (IOI19_walk)	C++17	10 / 100	4111 ms	511268 KiB

walk

#include "walk.h"
#include <bits/stdc++.h>
using namespace std;

int dist (array<int, 2> &a, array<int, 2> &b) {
	return abs(a[0] - b[0]) + abs(a[1] - b[1]);
}

long long min_distance(std::vector<int> x, std::vector<int> h, std::vector<int> l, std::vector<int> r, std::vector<int> y, int src, int snk) {
	vector<array<int, 2>> p;
	int n = x.size(), m = y.size();
	vector<vector<int>> adj;
	vector<int> seg[n + m], S[n], E[n];
	auto add = [&] (int i) {
		adj.push_back({i});
		seg[i].push_back(p.size());
	};
	auto add2 = [&] (int i, int j) {
		adj.push_back({i, j});
		seg[i].push_back(p.size());
		seg[j].push_back(p.size());
	};
	for (int i = 0; i < n; ++i) {
		add(i);
		p.push_back({x[i], 0});
		add(i);
		p.push_back({x[i], h[i]});
	}
	for (int i = 0; i < m; ++i) {
		add2(l[i], n + i);
		p.push_back({x[l[i]], y[i]});
		add2(r[i], n + i);
		p.push_back({x[r[i]], y[i]});
		S[l[i]].push_back(i);
		E[r[i]].push_back(i);
	}
	set<array<int, 2>> s;
	for (int i = 0; i < n; ++i) {
		for (int v : S[i]) {
			s.insert({y[v], v});
		}
		for (auto &v : s) {
			if (v[0] > h[i]) {
				break;
			}
			add2(i, n + v[1]);
			p.push_back({x[i], v[0]});
		}
		for (int v : E[i]) {
			s.erase({y[v], v});
		}
	}
	priority_queue<pair<long long, int>> pq;
	pq.push({0, 2 * src});
	vector<long long> dis(adj.size(), 1e18);
	dis[2 * src] = 0;
	while (pq.size()) {
		long long d = -pq.top().first;
		int u = pq.top().second;
		pq.pop();
		if (d != dis[u]) {
			continue;
		}
		for (int e : adj[u]) {
			auto l = lower_bound(seg[e].begin(), seg[e].end(), u);
			rotate(l, l + 1, seg[e].end());
			seg[e].pop_back();
			for (int v : seg[e]) {
				int dd = dist(p[u], p[v]);
				if (d + dd < dis[v]) {
					dis[v] = d + dd;
					pq.push({-dis[v], v});
				}
			}
		}
	}
	return dis[2 * snk] == 1e18 ? -1 : dis[2 * snk];
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 18
• Subtask 5: 0 / 43