Submission #771293

#	Time	Username	Problem	Language	Result	Execution time	Memory
771293		IBory	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	100 / 100	134 ms	74172 KiB

skyscraper

#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
#define pii pair<int, int>
using namespace std;

const int MAX = 30003;
vector<pii> G[MAX];
int D[MAX];

int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	int N, M, S, E;
	cin >> N >> M;
	map<pii, vector<int>> make;
	for (int i = 0; i < M; ++i) {
		int b, p;
		cin >> b >> p;
		if (i == 0) S = b;
		if (i == 1) E = b;
		make[{p, b % p}].push_back(b);
	}

	for (auto& [q, v] : make) {
		auto [p, init] = q;
		v.push_back(init);
		v.push_back(init + (N - 1 - init) / p * p);
		sort(v.begin(), v.end());
		for (int i = 1; i + 1 < v.size(); ++i) {
			int n = v[i] - p, d = 1;
			while (n >= v[i - 1]) {
				G[v[i]].emplace_back(n, d++);
				n -= p;
			}
			n = v[i] + p, d = 1;
			while (n <= v[i + 1]) {
				G[v[i]].emplace_back(n, d++);
				n += p;
			}
		}
	}

	memset(D, 0x3f, sizeof(D));
	priority_queue<pii, vector<pii>, greater<pii>> PQ; 
	PQ.emplace(D[S] = 0, S);
	while (!PQ.empty()) {
		auto [cd, cur] = PQ.top(); PQ.pop();
		if (cd > D[cur]) continue;
		if (cur == E) break;
		for (auto [next, nd] : G[cur]) {
			if (cd + nd >= D[next]) continue;
			PQ.emplace(D[next] = cd + nd, next);
		}
	}

	cout << (D[E] > 1E9 ? -1 : D[E]);
	return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:31:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |   for (int i = 1; i + 1 < v.size(); ++i) {
      |                   ~~~~~~^~~~~~~~~~
skyscraper.cpp:51:3: warning: 'E' may be used uninitialized in this function [-Wmaybe-uninitialized]
   51 |   if (cur == E) break;
      |   ^~

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