Submission #510294

#	Time	Username	Problem	Language	Result	Execution time	Memory
510294		thiago_bastos	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	57 / 100	1090 ms	12100 KiB

skyscraper

#include "bits/stdc++.h"
 
using namespace std;
 
using i64 = long long;
using u64 = unsigned long long;
using i32 = int;
using u32 = unsigned;
using i16 = short;
using u16 = unsigned short;
using ld = long double;
using ii = pair<int, int>;
 
const int N = 3e4 + 100, INF = 1e9;
 
vector<int> P[N], jumps[N], h[N];
 
int get_pos(int x, int p) {
	int k = lower_bound(h[x].begin(), h[x].end(), p) - h[x].begin();
	return k;
}
 
void solve() {
	int n, m;
 
	cin >> n >> m;
 
	vector<int> cnt(n, INF);
	queue<ii> q;
	vector<ii> a(m);
 
	int x0 = -1, x1 = -1;
 
	for(int i = 0; i < m; ++i) {
		int b, p;
		cin >> b >> p;
		if(!i) x0 = b;
		else if(i == 1) x1 = b;
		a[i] = {p, b};
	}
 
	sort(a.begin(), a.end());
 
	for(auto [p, b] : a) {
		if(!P[b].empty() && P[b].back() == p) continue;
		for(int x = b % p; x < n; x += p) {
			if(h[x].empty() || h[x].back() != p) {
				h[x].push_back(p);
				jumps[x].push_back(-1);
			}
		}
		P[b].push_back(p);
	}
 
	while(!P[x0].empty()) {
		int k = P[x0].back();
		P[x0].pop_back();
		int i = get_pos(x0, k);
		if(jumps[x0][i] == -1) {
			jumps[x0][i] = 0;
			q.emplace(x0, k);
		}
	}
 
	while(!q.empty()) {
		auto [x, p] = q.front();
		q.pop();
 
		int j = jumps[x][get_pos(x, p)];
	
		cnt[x] = min(cnt[x], j);
 
		if(x == x1) break;
 
		if(x >= p) {
			int k = get_pos(x - p, p);
			if(jumps[x - p][k] == -1) {
				jumps[x - p][k] = 1 + j;
				q.emplace(x - p, p);
			}
		}
 
		if(x + p < n) {
			int k = get_pos(x + p, p);
			if(jumps[x + p][k] == -1) {
				jumps[x + p][k] = 1 + j;
				q.emplace(x + p, p);
			}
		}
 
		while(!P[x].empty()) {
			int k = P[x].back();
 
			P[x].pop_back();
 
			if(x >= k) {
				int i = get_pos(x - k, k);
				if(jumps[x - k][i] == -1) {
					jumps[x - k][i] = 1 + j;
					q.emplace(x - k, k);
				}
			}
 
			if(x + k < n) {
				int i = get_pos(x + k, k);
				if(jumps[x + k][i] == -1) {
					jumps[x + k][i] = 1 + j;
					q.emplace(x + k, k);
				}
			}
		}
	}
 
	if(cnt[x1] == INF) cout << "-1\n";
	else cout << cnt[x1] << '\n';
}
 
int main() {
	ios_base :: sync_with_stdio(false);
	cin.tie(0);
	int t = 1;
	//cin >> t;
	while(t--) solve();
	return 0;
}

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