Submission #1051386

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051386		LittleOrange	Connecting Supertrees (IOI20_supertrees)	C++17	11 / 100	96 ms	22152 KiB

supertrees

#include "supertrees.h"
#include <vector>
#include<bits/stdc++.h>
using namespace std;
using ll = int;
struct dsu{
	ll n;
	vector<ll> p;
	dsu(ll N):n(N),p(N,-1){}
	ll g(ll i){
		return p[i]<0?i:p[i]=g(p[i]);
	}
	bool e(ll a, ll b){
		return g(a)==g(b);
	}
	bool m(ll a, ll b){
		a = g(a);
		b = g(b);
		if(a==b) return false;
		if (p[a]>p[b]) swap(a,b);
		p[a] += p[b];
		p[b] = a;
		return true;
	}
};

int construct(std::vector<std::vector<int>> p) {
	int n = p.size();
	vector<vector<ll>> ans(n,vector<ll>(n,0));
	dsu d(n);
	for(ll i = 0;i<n;i++) for(ll j = 0;j<n;j++){
		if (p[i][j]) d.m(i,j);
	}
	for(ll i = 0;i<n;i++) for(ll j = 0;j<n;j++){
		if (!p[i][j]&&d.e(i,j)) return 0;
	}
	vector<ll> g;
	for(ll i = 0;i<n;i++) if(d.g(i)==i) g.push_back(i);
	ll gc = g.size();
	vector<vector<ll>> gs(gc);
	for(ll i = 0;i<n;i++) gs[d.g(i)].push_back(i);
	for(auto &o : gs) if(o.size()>1){
		ll ty = p[o[0]][o[1]];
		for(ll i = 1;i<o.size();i++) ans[o[i-1]][o[i]] = ans[o[i]][o[i-1]] = 1;
		if (ty == 2){
			ans[o.front()][o.back()] = ans[o.back()][o.front()] = 1;
		}
	}
	build(ans);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:44:17: warning: comparison of integer expressions of different signedness: 'll' {aka 'int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |   for(ll i = 1;i<o.size();i++) ans[o[i-1]][o[i]] = ans[o[i]][o[i-1]] = 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