Submission #1212728

#	Time	Username	Problem	Language	Result	Execution time	Memory
1212728		madamadam3	Connecting Supertrees (IOI20_supertrees)	C++20	11 / 100	110 ms	22184 KiB

supertrees

#include "supertrees.h"
#include <bits/stdc++.h>

using namespace std;

#define sz(x) int((x).size())
#define bg(x) (x).begin()
#define en(x) (x).end()
#define all(x) bg((x)), en((x))
#define FOR(i, a, b) for (int i = a; i < b; i++)
#define pb push_back

using vi = vector<int>;
using vvi = vector<vi>;

struct DSU {
	int n; vector<int> par, siz;

	DSU(int N) {
		n = N;
		par.resize(n); iota(all(par), 0);
		siz.assign(n, 1);
	}

	int find(int v) {
		if (par[v] == v) return v;
		return par[v] = find(par[v]);
	}

	void unite(int a, int b) {
		a = find(a); b = find(b);
		if (a != b) {
			if (siz[a] < siz[b]) swap(a, b);
			par[b] = a;
			siz[a] += siz[b];
		}
	}
};

int construct(vvi p) {
	int n = sz(p);
	auto dsu = DSU(n);

	for (int i = 0; i < n; i++) {
		for (int j = i + 1; j < n; j++) {
			if (p[i][j] >= 1) dsu.unite(i, j);
		}
	}

	FOR(i, 0, n) {
		FOR(j, i+1, n) {
			if (p[i][j] == 0 && dsu.find(i) == dsu.find(j)) {
				return -1;
			}
		}
	}

	vvi cmps(n); FOR(i, 0, n) cmps[dsu.find(i)].pb(i);

	vvi answer(n, vector<int>(n, 0));
	FOR(cmpid, 0, n) {
		if (sz(cmps[cmpid]) <= 1) continue;
		int fst = cmps[cmpid][0], prev = cmps[cmpid][0];
		FOR(i, 1, sz(cmps[cmpid])) {
			answer[i][prev] = answer[prev][i] = 1;
			prev = cmps[cmpid][i];
		}

		if (p[fst][prev] == 2) {
			answer[fst][prev] = answer[prev][fst] = 1;
		}
	}


	build(answer);
	return 1;
}

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