Submission #1051380

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051380		Gromp15	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	116 ms	22116 KiB

supertrees

#include <bits/stdc++.h>
#include "supertrees.h"
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
using namespace std;

struct dsu {
	vector<int> p, size;
	dsu(int n) : p(n), size(n, 1) {
		iota(all(p), 0);
	}
	int get(int v) {
		return v == p[v] ? v : p[v] = get(p[v]);
	}
	bool merge(int a, int b) {
		a = get(a), b = get(b);
		if (a == b) return 0;
		if (size[a] < size[b]) swap(a, b);
		size[a] += size[b], p[b] = a;
		return 1;
	}
};

int construct(std::vector<std::vector<int>> p) {
	int n = sz(p);
	dsu d(n), d2(n), d3(n);
	for (int i = 0; i < n; i++) for (int j = i+1; j < n; j++) {
		if (p[i][j]) d.merge(i, j);
		if (p[i][j] == 1) d2.merge(i, j);
		if (p[i][j] == 2) d3.merge(i, j);
		if (p[i][j] == 3) return 0;
	}
	for (int i = 0; i < n; i++) for (int j = i+1; j < n; j++) if (!p[i][j] && d.get(i) == d.get(j)) return 0;
	vector<vector<int>> ans(n, vector<int>(n));
	vector<int> leaders;
	for (int i = 0; i < n; i++) { 
		if (i == d2.get(i)) leaders.emplace_back(i);
		else ans[i][d2.get(i)] = ans[d2.get(i)][i] = 1;
	}
	vector<vector<int>> comp(n);
	for (int v : leaders) comp[d3.get(v)].emplace_back(v);
	for (int i = 0; i < n; i++) if (comp[i].size() > 1) {
		if (comp[i].size() == 2) return 0;
		for (int j = 0; j < sz(comp[i]); j++) {
			int v = comp[i][j], u = comp[i][(j+1)%sz(comp[i])];
			ans[v][u] = ans[u][v] = 1;
		}
	}
	build(ans);
	return 1;
}

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