Submission #76361

#	Time	Username	Problem	Language	Result	Execution time	Memory
76361		shoemakerjo	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	100 / 100	163 ms	16504 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;
#define maxn 30010
#define pii pair<int, int>

int N, M;
priority_queue<pii, vector<pii>, greater<pii>> pq;

const int inf = 987654321;
vector<vector<int>> mov(maxn);
int dist[maxn];

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cin >> N >> M;
	int source, sink;
	int b, p;
	for (int i = 0; i < M; i++) {
		cin >> b >> p;
		mov[b].push_back(p);
		if (i == 0) source = b;
		if (i == 1) sink = b;
	}
	for (int i = 0; i < N-1; i++) {
		sort(mov[i].begin(), mov[i].end());
	}
	fill(dist, dist+maxn, inf);
	dist[source] = 0;

	pq.push(pii(0, source));
	while (pq.size()) {
		pii cur = pq.top(); pq.pop();
		int spot = cur.second;
		int d = cur.first;
		if (d > dist[spot]) continue;
		if (spot == sink) break;
		int prev = -1;

		for (int val : mov[spot]) {
			if (val == prev) continue;
			prev = val;
			for (int jp = 1; jp < N; jp++) {
				int nx = jp*val + spot;
				if (nx >= N) break;
				if (d + jp < dist[nx]) {
					dist[nx] = d+jp;
					pq.push(pii(d+jp, nx));
				}
				if (binary_search(mov[nx].begin(), mov[nx].end(), val)) break;
			}
			for (int jp = 1; jp < N; jp++) {
				int nx = spot - jp*val;
				if (nx < 0) break;
				if (nx >= N) break;
				if (d + jp < dist[nx]) {
					dist[nx] = d+jp;
					pq.push(pii(d+jp, nx));
				}
				if (binary_search(mov[nx].begin(), mov[nx].end(), val)) break;
			}
		}
	}



	if (dist[sink] == inf) dist[sink] = -1;
	cout << dist[sink] << endl;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:38:3: warning: 'sink' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (spot == sink) break;
   ^~

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