Submission #1273837

#	Time	Username	Problem	Language	Result	Execution time	Memory
1273837		crispxx	Connecting Supertrees (IOI20_supertrees)	C++20	0 / 100	2 ms	348 KiB

supertrees

#include "supertrees.h"

#include <bits/stdc++.h>
using namespace std;

// #define int long long
#define all(x) x.begin(), x.end()
#define pb push_back
#define ar array
#define nl '\n'

struct dsu {
	vector<int> p, sz;
	
	dsu(int n) : p(n), sz(n) {
		iota(all(p), 0);
	}
	
	int find(int v) {
		return v == p[v] ? v : p[v] = find(p[v]);
	}
	
	void unite(int u, int v) {
		u = find(u), v = find(v);
		if(u == v) return;
		if(sz[u] < sz[v]) swap(u, v);
		p[v] = u;
		sz[u] += sz[v];
	}
};

int construct(std::vector<std::vector<int>> p) {
	int n = p.size();
	
	dsu d(n);
	
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			if(p[i][j]) {
				d.unite(i, j);
			}
		}
	}
	
	vector<vector<int>> v(n);
	vector<vector<int>> b(n, vector<int>(n));
	
	for(int i = 0; i < n; i++) {
		v[d.find(i)].pb(i);
	}
	
	for(int i = 0; i < n; i++) {
		auto &u = v[i];
		
		set<int> st;
		
		for(int j = 0; j < (int)u.size(); j++) {
			for(int k = 0; k < (int)u.size(); k++) {
				if( u[j] == u[k] ) continue;
				if( p[ u[j] ][ u[k] ] == 1 ) {
					b[ u[j] ][ u[k] ] = 1;
				} else if( p[ u[j] ][ u[k] ] == 2 ) {
					st.emplace(u[j]);
					st.emplace(u[k]);
				}
			}
		}
		
		if(!st.empty()) {
			
			assert(st.size() > 2);
			
			int last = *(--st.end());
			
			for(auto j : st) {
				b[j][last] = b[last][j] = 1;
				last = j;
			}
			
		}
		
	}
	
	build(b);
	
	return true;
}

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