Submission #47171

#	Time	Username	Problem	Language	Result	Execution time	Memory
47171		platypus	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	36 / 100	1085 ms	134584 KiB

skyscraper

#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <cstring>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <list>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <unordered_set>
#include <unordered_map>
#include <array>
#include <cassert>
#include <bitset>
using namespace std;
using LL = long long;

namespace std {
	template <>
	class hash<std::pair<int, int>> {
	public:
		size_t operator()(const std::pair<int, int>& x) const {
			//return hash<int>()(x.first) ^ hash<int>()(x.second);
			return (size_t)(x.second ^ x.first + 0x9e3779b9 + (x.second << 6) + (x.second >> 2));
		}
	};
}

//Vは比較可能な値にする
template <typename V>
class Graph {
private:
	//unordered_map<V, vector<pair<V, LL>>>edge;
	vector<pair<pair<V, V>, LL>>raw;
	vector<V>vset;
public:
	//from->toへcostの辺を張る
	void addEdge(V from, V to, LL cost) {
		//edge[from].push_back(make_pair(to, cost));
		raw.push_back(make_pair(make_pair(from, to), cost));
		vset.push_back(from);
		vset.push_back(to);
	}
	//v1とv2間にcostの辺を張る
	void addUndirectedEdge(V v1, V v2, LL cost) {
		//edge[v1].push_back(make_pair(v2, cost));
		//edge[v2].push_back(make_pair(v1, cost));
		raw.push_back(make_pair(make_pair(v1, v2), cost));
		raw.push_back(make_pair(make_pair(v2, v1), cost));
		vset.push_back(v1);
		vset.push_back(v2);
	}
	//最短を求める
	void dijkstra(V start, map<V, LL>&dist) {
		sort(vset.begin(), vset.end());
		vset.erase(unique(vset.begin(), vset.end()), vset.end());
		int vnum = vset.size();
		vector<LL>disti(vnum, LLONG_MAX / 9);
		unordered_map<V, int>inv;
		for (int i = 0; i < vnum; ++i) {
			inv[vset[i]] = i;
		}
		vector<vector<pair<int, LL>>>edgei(vnum);
		for (auto& e : raw) {
			edgei[inv[e.first.first]].push_back(make_pair(inv[e.first.second], e.second));
		}
		//dist[start] = 0;
		//priority_queue<pair<LL, V>, vector<pair<LL, V>>, greater<pair<LL, V>>>que;
		disti[inv[start]] = 0;
		priority_queue<pair<LL, int>, vector<pair<LL, int>>, greater<pair<LL, int>>>que;
		que.push(make_pair(0LL, inv[start]));
		while (!que.empty()) {
			auto q = que.top();
			que.pop();
			int now = q.second;
			LL dis = q.first;
			if (disti[now] < dis) continue;
			for (auto e : edgei[now]) {
				int nxt = e.first;
				LL cost = e.second;
				if (/*!disti.count(nxt)  ||*/ disti[nxt] > disti[now] + cost) {
					disti[nxt] = disti[now] + cost;
					que.push(make_pair(disti[nxt], nxt));
				}
			}
		}
		for (int i = 0; i < vnum; ++i) {
			dist[vset[i]] = disti[i];
		}
	}
};

int N, M;

int mceil(int a, int b) {
	if (a == 0)return 0;
	return (a - 1) / b + 1;
}

int main(void)
{
	cin >> N >> M;
	using P = pair<int, int>;
	map<P, vector<int>>mp;
	int st = -1;
	int enb = -1, enp = -1, enr = -1;
	for (int i = 0; i < M; ++i) {
		int b, p;
		cin >> b >> p;
		if (i == 0)st = b;
		if (i == 1) {
			enb = b;
			enp = p;
			enr = b % p;
		}
		int rem = b % p;
		mp[make_pair(p, rem)].push_back(b);
	}
	Graph<P>G;
	for (auto elm : mp) {
		int p = elm.first.first;
		int rem = elm.first.second;
		auto& v = elm.second;
		int len = mceil(N - rem, p);
		vector<LL>dist(len, INT_MAX);
		for (int x : v)dist[x / p] = 0;
		/*for (int i = 1; i < len; ++i) {
			dist[i] = min(dist[i - 1] + 1, dist[i]);
		}
		for (int i = len - 1; i > 0; --i) {
			dist[i - 1] = min(dist[i] + 1, dist[i - 1]);
		}*/
		for (int i = 0; i < len; ++i) {
			if (dist[i] < INT_MAX)G.addEdge(P(0, i * p + rem), P(p, i * p + rem), dist[i]);
			G.addEdge(P(p, i * p + rem), P(0, i * p + rem), 0LL);
		}
		for (int i = 1; i < len; ++i) {
			G.addUndirectedEdge(P(p, (i - 1)*p + rem), P(p, i*p + rem), 1LL);
		}
	}
	int len = mceil(N - enr, enp);
	for (int i = 0; i < len; ++i) {
		if (abs(i - (enb / enp)) == 0)
			G.addEdge(P(0, i * enp + enr), P(N, i * enp + enr), abs(i - (enb / enp)));
	}
	map<P, LL> dist;
	G.dijkstra(P(0, st), dist);
	LL ans = LLONG_MAX;
	for (int i = 0; i < len; ++i) {
		if (abs(i - (enb / enp)) == 0 && dist.count(P(N, i * enp + enr)))
			ans = min(ans, dist[P(N, i * enp + enr)]);
	}
	if (ans >= LLONG_MAX / 9) {
		cout << -1 << endl;
	}
	else {
		cout << ans << endl;
	}
	return 0;
}

Compilation message (stderr)

skyscraper.cpp: In member function 'std::size_t std::hash<std::pair<int, int> >::operator()(const std::pair<int, int>&) const':
skyscraper.cpp:36:70: warning: suggest parentheses around arithmetic in operand of '^' [-Wparentheses]
    return (size_t)(x.second ^ x.first + 0x9e3779b9 + (x.second << 6) + (x.second >> 2));
                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 14 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 43