Submission #585364

#	Time	Username	Problem	Language	Result	Execution time	Memory
585364		GusterGoose27	Jakarta Skyscrapers (APIO15_skyscraper)	C++11	10 / 100	4 ms	4080 KiB

skyscraper

#pragma GCC optimize ("O3")

#include <bits/stdc++.h>
 
using namespace std;
 
typedef pair<int, int> pii;
 
const int MAXN = 3e4;
const int inf = 1e9;
vector<pii> edges[MAXN];
unordered_set<int> at[MAXN];
int n, m;
int dist[MAXN];
vector<int> jump_occs[MAXN+1];
int occ_pos[MAXN+1];
vector<int> valsat[MAXN];
int posf;
 
void dijkstra(int s) {
	fill(dist, dist+n, inf);
	dist[s] = 0;
	priority_queue<pii> pq;
	pq.push(pii(0, s));
	while (!pq.empty()) {
		pii p = pq.top();
		pq.pop();
		int cur = p.second;
		if (cur == posf) return;
		if (dist[cur] < p.first) continue;
		for (pii e: edges[cur]) {
			if (dist[cur]+e.second < dist[e.first]) {
				dist[e.first] = dist[cur]+e.second;
				pq.push(pii(dist[e.first], e.first));
			}
		}
	}
}
 
int main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL);
	cin >> n >> m;
	int poss;
	for (int i = 0; i < m; i++) {
		int x, y; cin >> x >> y;
		if (i == 1) posf = x;
		if (i == 0) poss = x;
		jump_occs[y].push_back(x);
		occ_pos[y]++;
		//valsat[x].push_back(y);
		at[x].insert(y);
	}
	for (int i = n-1; i >= 0; i--) {
		for (int p: at[i]) {
			occ_pos[p]--;
			int cur = occ_pos[p];
			int psize = jump_occs[p].size();
			for (int j = i+p; j < n; j += p) {
				edges[i].push_back(pii(j, (j-i)/p));
				while (cur < psize && jump_occs[p][cur] < j) cur++;
				if (cur < psize && jump_occs[p][cur] == j) break;
			}
		}
	}
	for (int i = 0; i < n; i++) {
		for (int p: at[i]) {
			int cur = occ_pos[p];
			for (int j = i-p; j >= 0; j -= p) {
				edges[i].push_back(pii(j, (i-j)/p));
				while (cur >= 0 && jump_occs[p][cur] > j) cur--;
				if (cur >= 0 && jump_occs[p][cur] == j) break;
			}
			occ_pos[p]++;
		}
	}
	dijkstra(poss);
	cout << ((dist[posf] == inf) ? (-1) : dist[posf]) << "\n";
	return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:76:10: warning: 'poss' may be used uninitialized in this function [-Wmaybe-uninitialized]
   76 |  dijkstra(poss);
      |  ~~~~~~~~^~~~~~

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