Submission #1084746

#	Time	Username	Problem	Language	Result	Execution time	Memory
1084746		an22inkle	Connecting Supertrees (IOI20_supertrees)	C++17	40 / 100	150 ms	24148 KiB

supertrees

#include<bits/stdc++.h>
#include "supertrees.h"
using pair = std::array<int, 2>;
using ll = long long;

void stress(std::vector<std::vector<int>> p, std::vector<std::vector<int>> ans) {
	int n = p.size();
	std::vector<std::vector<int>> hits(n, std::vector<int>(n));
	auto adj = hits;

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
				if (i == j or ans[i][j] == 0) continue;
				adj[i].push_back(j);
				adj[j].push_back(i);
		}
	}

	std::function<int(int, int, int)> dfs = [&](int u, int parent, int target) {
		if (target == u) return 1;
		int res = 0;
		for (auto v : adj[u]) {
			if (parent == v) continue;
			res += dfs(v, u, target);
		}
		return res;
	};

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (i == j) hits[i][i] = 1;
			else hits[i][j] = dfs(i, -1, j);

			if (hits[i][j] != p[i][j]) {
				std::cout << "mismatch\n" << i << ' ' << j << " expected " << p[i][j] << " got " << hits[i][j] << '\n';;
			}
		}
	}

	std::cout << "stress test ok\n";
}

int construct(std::vector<std::vector<int>> p) {
	int n = p.size();
	std::vector<std::vector<int>> ans(n, std::vector<int>(n)), lines;
	std::vector<int> part(n, -1);

	int max = 0;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (i == j || p[i][j] == 0) continue;
	
			if (part[i] > -1 && part[j] > -1) {
				if (part[i] != part[j]) return 0;
				continue;
			}

			max = std::max(p[i][j], max);
			if (part[i] > -1) lines[part[i]].push_back(j), part[j] = part[i];
			else if (part[j] > -1) lines[part[j]].push_back(i), part[i] = part[j];
			else {
				lines.push_back({});
				lines.back().push_back(i);
				lines.back().push_back(j);
				part[i] = part[j] = lines.size() - 1;
			}
		}
	}

	for (auto line : lines) {
		if (max == 2 && line.size() == 2) return 0;
		for (int i = 0; i < line.size(); i++) {
			for (int j = i+1; j < line.size(); j++) {
				if (p[line[i]][line[j]] == 0) return 0;
			}
			// std::cout << line[i] << ' ';
			if (max == 2) {
				ans[line[i]][line[(i+1)%line.size()]] = ans[line[(i + 1)%line.size()]][line[i]] = 1;	
			} else {
				if (i != line.size() - 1) ans[line[i]][line[(i+1)]] = ans[line[(i + 1)]][line[i]] = 1;	
			}
			
		} // std::cout << '\n';
	}

	build(ans);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:72:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |   for (int i = 0; i < line.size(); i++) {
      |                   ~~^~~~~~~~~~~~~
supertrees.cpp:73:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |    for (int j = i+1; j < line.size(); j++) {
      |                      ~~^~~~~~~~~~~~~
supertrees.cpp:80:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |     if (i != line.size() - 1) ans[line[i]][line[(i+1)]] = ans[line[(i + 1)]][line[i]] = 1;
      |         ~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 10 / 10
• Subtask 3: 19 / 19
• Subtask 4: 0 / 35
• Subtask 5: 0 / 21
• Subtask 6: 0 / 4