Submission #771266

#	Time	Username	Problem	Language	Result	Execution time	Memory
771266		IBory	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	57 / 100	207 ms	256780 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 = 2222222;
vector<int> G[MAX];
bool noL[MAX];
int D[MAX];

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

	int node = N + 1, SN, EN;
	for (auto& [q, v] : make) {
		auto [p, i] = q;
		if (!i) i += p;
		vector<int> fr;
		for (int j = i; j <= N; j += p) {
			if (S == pii{ j, p }) SN = node;
			if (E == pii{ j, p }) EN = node;
			G[node].push_back(-j);
			fr.push_back(node++);
		}
		noL[fr[0]] = noL[fr.back() + 1] = 1;
		for (int n : v) {
			G[n].push_back(-fr[(n - 1) / p]);
		}
	}
	make.clear();
	for (int i = 1; i <= N; ++i) noL[i] = 1;

	memset(D, 0x3f, sizeof(D));
	D[SN] = 0;
	deque<int> Q;
	Q.push_back(SN);
	while (!Q.empty()) {
		int cur = Q.front(); Q.pop_front();
		if (cur == EN) break;
		if (!noL[cur]) G[cur].push_back(cur - 1);
		if (!noL[cur + 1]) G[cur].push_back(cur + 1);

		for (int next : G[cur]) {
			int d = 1;
			if (next < 0) {
				d = 0;
				next *= -1;
			}
			if (D[cur] + d >= D[next]) continue;
			D[next] = D[cur] + d;
			if (d == 0) Q.push_front(next);
			else Q.push_back(next);
		}

		if (!noL[cur]) G[cur].pop_back();
		if (!noL[cur + 1]) G[cur].pop_back();
	}

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

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:73:15: warning: 'EN' may be used uninitialized in this function [-Wmaybe-uninitialized]
   73 |  cout << (D[EN] > 1E9 ? -1 : D[EN]);
      |           ~~~~^

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