Submission #155088

#	Time	Username	Problem	Language	Result	Execution time	Memory
155088		wakaka	Sky Walking (IOI19_walk)	C++14	100 / 100	2914 ms	116868 KiB

walk

#include "walk.h"
#include <bits/stdc++.h>
using namespace std;
//#define cerr if (false) cerr
#define db(x) cerr << #x << "=" << x << endl
#define db2(x, y) cerr << #x << "=" << x << "," << #y << "=" << y << endl
#define db3(x, y, z) cerr << #x << "=" << x << "," << #y << "=" << y << "," << #z << "=" << z << endl
#define dbv(v) cerr << #v << "="; for (auto _x : v) cerr << _x << ", "; cerr << endl
#define dba(a, n) cerr << #a << "="; for (int _i = 0; _i < (n); ++_i) cerr << a[_i] << ", "; cerr << endl
template <typename A, typename B>
ostream& operator<<(ostream& os, const pair<A, B>& x) {
	return os << "(" << x.first << "," << x.second << ")";
}
typedef long long ll;
typedef long double ld;
ll min_distance(vector<int> x, vector<int> h, vector<int> l, vector<int> r, vector<int> y, int s, int g) {
	int n = x.size();
	int m = l.size();
	vector<vector<int>> vert(n), hor(m);
	vector<vector<pair<int, int>>> events(n);
	for (int i = 0; i < m; ++i) {
		events[l[i]].emplace_back(i, 1);
		events[r[i]].emplace_back(i, -1);
	}
	set<pair<int, int>> S;
	for (int i = 0; i < n; ++i) {
		for (auto& e : events[i]) {
			int j = e.first;
			vert[i].push_back(y[j]);
			hor[j].push_back(x[i]);
			if (e.second == 1) S.insert({y[j], j});
		}
		vector<int> nvert;
		for (int yj : vert[i]) {
			auto it = S.lower_bound({yj, -1});
			if (it == S.begin()) continue;
			int k = prev(it)->second;
			hor[k].push_back(x[i]);
			nvert.push_back(y[k]);
		}
		vert[i].insert(vert[i].end(), nvert.begin(), nvert.end());
		if (i == s || i == g) vert[i].push_back(0);
		for (auto& e : events[i]) {
			int j = e.first;
			if (e.second == -1) S.erase({y[j], j});
		}
	}
	auto f = [&](int q) {
		vector<pair<int, int>> lhs = {{h[q], q}}, rhs = {{h[q], q}};
		for (int i = q - 1; i >= 0; --i) {
			if (h[i] > lhs.back().first) lhs.push_back({h[i], i});
		}
		for (int i = q + 1; i < n; ++i) {
			if (h[i] > rhs.back().first) rhs.push_back({h[i], i});
		}
		for (int i = 0; i < m; ++i) {
			if (r[i] < q || l[i] > q) continue;
			auto it = lower_bound(lhs.begin(), lhs.end(), make_pair(y[i], -1));
			if (it == lhs.end()) continue;
			int p = it->second;
			if (p < l[i]) continue;
			vert[p].push_back(y[i]);
			hor[i].push_back(x[p]);
		}
		for (int i = 0; i < m; ++i) {
			if (r[i] < q || l[i] > q) continue;
			auto it = lower_bound(rhs.begin(), rhs.end(), make_pair(y[i], -1));
			if (it == rhs.end()) continue;
			int p = it->second;
			if (p > r[i]) continue;
			vert[p].push_back(y[i]);
			hor[i].push_back(x[p]);
		}
	};
	f(s);
	f(g);
	map<pair<int, int>, int> mp;
	auto getId = [&](pair<int, int> a) {
		auto it = mp.find(a);
		if (it != mp.end()) return it->second;
		int s = mp.size();
		return mp[a] = s;
	};
	for (int i = 0; i < n; ++i)
		for (int j : vert[i]) getId({x[i], j});
	for (int i = 0; i < m; ++i)
		for (int j : hor[i]) getId({j, y[i]});
	vector<vector<pair<int, int>>> E(mp.size());
	for (int i = 0; i < n; ++i) {
		sort(vert[i].begin(), vert[i].end());
		vert[i].resize(unique(vert[i].begin(), vert[i].end()) - vert[i].begin());
		for (int j = 0; j + 1 < vert[i].size(); ++j) {
			int u = getId({x[i], vert[i][j]});
			int v = getId({x[i], vert[i][j + 1]});
			int d = vert[i][j + 1] - vert[i][j];
			E[u].push_back({v, d});
			E[v].push_back({u, d});
		}
	}
	for (int i = 0; i < m; ++i) {
		sort(hor[i].begin(), hor[i].end());
		hor[i].resize(unique(hor[i].begin(), hor[i].end()) - hor[i].begin());
		for (int j = 0; j + 1 < hor[i].size(); ++j) {
			int u = getId({hor[i][j], y[i]});
			int v = getId({hor[i][j + 1], y[i]});
			int d = hor[i][j + 1] - hor[i][j];
			E[u].push_back({v, d});
			E[v].push_back({u, d});
		}
	}
	const ll INF = 1LL << 60;
	vector<ll> dist(mp.size(), INF);
	int src = getId({x[s], 0}), dest = getId({x[g], 0});
	typedef pair<ll, int> Pair;
	priority_queue<Pair, vector<Pair>, greater<Pair>> pq;
	dist[src] = 0;
	pq.emplace(dist[src], src);
	while (!pq.empty()) {
		int u = pq.top().second;
		ll cdist = pq.top().first;
		pq.pop();
		if (cdist > dist[u]) continue;
		for (auto e : E[u]) {
			int v = e.first;
			ll val = dist[u] + e.second;
			if (val < dist[v]) {
				dist[v] = val;
				pq.emplace(val, v);
			}
		}
	}
	return dist[dest] == INF ? -1 : dist[dest];
}

Compilation message (stderr)

walk.cpp: In function 'll min_distance(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>, int, int)':
walk.cpp:92:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 0; j + 1 < vert[i].size(); ++j) {
                   ~~~~~~^~~~~~~~~~~~~~~~
walk.cpp:103:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 0; j + 1 < hor[i].size(); ++j) {
                   ~~~~~~^~~~~~~~~~~~~~~

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