Submission #823616

#	Time	Username	Problem	Language	Result	Execution time	Memory
823616		GusterGoose27	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	198 ms	24068 KiB

supertrees

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

const int MAXN = 1e3+5;

using namespace std;
int n;
int uf[MAXN];

int find(int i) {
	return uf[i] == i ? i : uf[i] = find(uf[i]);
}

void merge(int a, int b) {
	a = find(a);
	b = find(b);
	assert(a != b);
	uf[a] = b;
}

bool vis[MAXN];

int construct(vector<vector<int>> p) {
	n = p.size();
	iota(uf, uf+n, 0);
	vector<vector<int>> answer(n, vector<int>(n, 0));
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (p[i][j] == 3) return 0;
			if (find(i) != find(j) && p[i][j] == 1) {
				answer[i][j] = answer[j][i] = 1;
				merge(i, j);
			}
		}
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (p[i][j] == 1 && find(i) != find(j)) return 0;
			if (p[i][j] != 1 && find(i) == find(j)) return 0;
		}
	}
	// all 1 connections are dealt with
	for (int i = 0; i < n; i++) {
		vector<int> vals;
		int cur = find(i);
		if (vis[cur]) continue;
		do {
			if (vals.size()) merge(vals.back(), cur);
			vals.push_back(cur);
			vis[cur] = 1;
			bool f = 0;
			for (int j = 0; j < n; j++) {
				if (uf[j] != j || vis[j] || j == find(i)) continue;
				if (p[cur][j] == 2) {
					f = 1;
					cur = j;
					break;
				}
			}
			if (!f) cur = find(i);
		} while (cur != find(i));
		if (vals.size() == 2) return 0;
		if (vals.size() > 1) {
			for (int j = 0; j < vals.size(); j++) {
				answer[vals[j]][vals[(j+1)%vals.size()]] = 
				answer[vals[(j+1)%vals.size()]][vals[j]] = 1;
			}
		}
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (p[i][j] >= 1 && find(i) != find(j)) return 0;
			if (p[i][j] == 0 && find(i) == find(j)) return 0;
		}
	}
	build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:64:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |    for (int j = 0; j < vals.size(); j++) {
      |                    ~~^~~~~~~~~~~~~

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