Submission #1165032

#	Time	Username	Problem	Language	Result	Execution time	Memory
1165032		baldwin_huang	Rainforest Jumps (APIO21_jumps)	C++20	0 / 100	4046 ms	19088 KiB

jumps

#include <bits/stdc++.h>

using namespace std;

int n;
const int INF = 1e9;

struct node {
	int left = -1;
	int right = -1;
};

vector<node> nodes;

void init(int N, vector<int> H) {
	n = N;
	nodes = vector<node>(n);

	// Precomputing the left value.
	set<int> heights_l;
	vector<int> last_val_l(n + 1, -1);
	for (int i = 0; i < n; i++) {
		auto it = heights_l.upper_bound(H[i]);
		if (it != heights_l.end()) {
			nodes[i].left = last_val_l[*it];
		}
		heights_l.insert(H[i]);
		last_val_l[H[i]] = i;
	}
	// Precomputing the right values.
	set<int> heights_r;
	vector<int> last_val_r(n + 1, -1);
	for (int i = n - 1; i >= 0; i--) {
		auto it = heights_r.upper_bound(H[i]);
		if (it != heights_r.end()) {
			nodes[i].right = last_val_r[*it];
		}
		heights_r.insert(H[i]);
		last_val_r[H[i]] = i;
	}

	// for (int i = 0; i < n; i++) {
	// 	cout << "Node " << i << ": " << nodes[i].left << ' ' << nodes[i].right << '\n';
	// }

	return;
}

int minimum_jumps(int A, int B, int C, int D) {

	// Start the BFS

	vector<int> dist(n, INF);
	queue<int> q;

	// cout << A << ' ' << B << ' ' << nodes.size() << '\n';

	for (int i = A; i <= B; i++) {
		dist[i] = 0;
		q.push(i);
	}

	while (!q.empty()) {
		int source = q.front(); q.pop();
		// cout << "Source: " << source << '\n';

		if (dist[nodes[source].left] == INF) {
			q.push(nodes[source].left);
			dist[nodes[source].left] = 1 + dist[source];
		}
		if (dist[nodes[source].right] == INF) {
			q.push(nodes[source].right);
			dist[nodes[source].right] = 1 + dist[source];
		}
	}

	int smallest = INF;
	for (int i = C; i <= D; i++) {
		smallest = min(smallest, dist[i]);
	}

	if (smallest == INF) {
		return -1;
	}
	return smallest;
}

• Subtask 1: 0 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 13
• Subtask 4: 0 / 12
• Subtask 5: 0 / 23
• Subtask 6: 0 / 21
• Subtask 7: 0 / 19