Submission #1253331

#	Time	Username	Problem	Language	Result	Execution time	Memory
1253331		TIN	World Map (IOI25_worldmap)	C++20	72 / 100	81 ms	9544 KiB

worldmap

#include "worldmap.h"
#include <functional>

std::vector<std::vector<int>> create_map(int N, int M, std::vector<int> A, std::vector<int> B) {
	std::vector<std::vector<int>> ans(2 * N, std::vector<int>(2 * N, 1));
	for (auto& x : A) --x; for (auto& x : B) --x;
	std::vector<std::vector<int>> adj(N, std::vector<int>());
	for (int i = 0; i < M; i++) adj[A[i]].push_back(B[i]), adj[B[i]].push_back(A[i]);
	std::vector<int> euler_tour;
	if (M == N - 1) {
		bool sub1 = true;
		for (int i = 0; i + 1 < N; i++) if (A[i] != i || B[i] != i + 1) sub1 = false;
		if (sub1) {
			for (int i = 0; i < 2 * N; i++) for (int j = 0; j < 2 * N; j++) ans[i][j] = N;
			for (int i = 1; i < N; i++) for (int j = 0; j < 2 * N; j++) ans[i - 1][j] = i;
		} else {
			for (int i = 0; i < 2 * N; i++) for (int j = 0; j < 2 * N; j++) ans[i][j] = 1;
			std::function<void(int, int)> DFS;
			DFS = [&](int u, int par) {
				euler_tour.push_back(u + 1);
				for (int v : adj[u]) {
					if (v ^ par) {
						DFS(v, u);
						euler_tour.push_back(u + 1);
					}
				}
			};
			DFS(0, 0);
			for (int i = 0; i < (int) euler_tour.size(); i++) for (int j = 0; j < 2 * N; j++) ans[i][j] = euler_tour[i];
		}
		return ans;
	}
	if (M == N * (N - 1) / 2) {
		for (int i = 0; i < N; i++) {
			for (int j = 0; j < 2 * N; j++) {
				ans[i * 2][j] = i + 1;
				ans[i * 2 + 1][j] = (j + 1 <= N ? j + 1 : N);
			}
		}
		return ans;
	}
	bool sub4 = true;
	std::vector<bool> ok(N, false);
	for (int i = 0; i < M; i++) if (A[i] == 0 || B[i] == 0) ok[A[i] + B[i]] = true;
	for (int i = 1; i < N; i++) if (!ok[i]) sub4 = false;
	if (sub4) {
		for (int i = 0; i < 2 * N; i++) for (int j = 0; j < 2 * N; j++) ans[i][j] = 1;
		for (int i = 0; i < N; i++) {
			int row = i * 2;
			for (int j = 0; j < 2 * N; j++) ans[row][j] = i + 1;
			for (int j = 0; j < (int) adj[i].size(); j++) ans[row][j * 2] = adj[i][j] + 1;
		}
		return ans;
	}
	std::vector<bool> visited(N, false);
	std::function<void(int)> DFS;
	DFS = [&](int u) {
		visited[u] = true;
		euler_tour.push_back(u + 1);
		for (int v : adj[u]) {
			if (!visited[v]) {
				DFS(v);
				euler_tour.push_back(u + 1);
			}
		}
	};
	DFS(0);
	ans.assign(4 * N, std::vector<int>(4 * N, 1));
	int row = 0;
	visited.assign(N, false);
	for (int i = 0; i < (int) euler_tour.size(); i++) {
		int u = euler_tour[i];
		if (visited[u - 1]) {
			for (int j = 0; j < 4 * N; j++) ans[row][j] = u;
			++row;
			continue;
		}
		for (int j = 0; j < 4 * N; j++) ans[row][j] = ans[row + 1][j] = ans[row + 2][j] = u;
		for (int j = 0; j < (int) adj[u - 1].size(); j++) ans[row + 1][j * 2] = adj[u - 1][j] + 1;
		row += 3;
		visited[u - 1] = true;
	}
	return ans;
}

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 7 / 7
• Subtask 4: 8 / 8
• Subtask 5: 14 / 14
• Subtask 6: 28 / 56