Submission #212726

#	Time	Username	Problem	Language	Result	Execution time	Memory
212726		spdskatr	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	57 / 100	1097 ms	70608 KiB

skyscraper

#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <queue>
#include <unordered_map>
#include <unordered_set>

using namespace std;

int N, M, b[30005], p[30005], seen[30005];
unordered_set<int> doges[30005];
unordered_map<int, int> dists;
queue<int> q;

int id(int d, int x) {
	return d * 30001 + x;
}

void visit(int pos, int d) {
	seen[pos] = 1;
	for (int doge : doges[pos]) {
		if (dists.find(id(pos, doge)) == dists.end()) {
			dists[id(pos, doge)] = d;
			q.push(id(pos, doge));
		}
	}
}

int main() {
	scanf("%d %d", &N, &M);
	for (int i = 0; i < M; i++) {
		scanf("%d %d", b+i, p+i);
		doges[b[i]].insert(p[i]);
	}
	visit(b[0], 0);
	while (q.size()) {
		int e = q.front(); q.pop();
		int loc = e / 30001, power = e % 30001;
		if (loc == b[1]) {
			printf("%d\n", dists[e]);
			return 0;
		}
		if (loc - power >= 0) {
			int pos = loc - power;
			int d = power;
			if (!seen[pos]) {
				visit(pos, dists[e] + 1);
			}
			if (dists.find(id(pos, d)) == dists.end()) {
				dists[id(pos, d)] = dists[e] + 1;
				q.push(id(pos, d));
			}
		}
		if (loc + power < N) {
			int pos = loc + power;
			int d = power;
			if (!seen[pos]) {
				visit(pos, dists[e] + 1);
			}
			if (dists.find(id(pos, d)) == dists.end()) {
				dists[id(pos, d)] = dists[e] + 1;
				q.push(id(pos, d));
			}
		}
	}
	printf("-1\n");
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:31:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &N, &M);
  ~~~~~^~~~~~~~~~~~~~~~~
skyscraper.cpp:33:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", b+i, p+i);
   ~~~~~^~~~~~~~~~~~~~~~~~~

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