Submission #984326

#	Time	Username	Problem	Language	Result	Execution time	Memory
984326		CSQ31	Connecting Supertrees (IOI20_supertrees)	C++17	100 / 100	179 ms	38160 KiB

supertrees

#include "supertrees.h"
#include<bits/stdc++.h>
using namespace std;
#define sz(a) (int)(a.size())
int p[1111][1111],q[1111][1111],ans[1111][1111];
void add(int v,int u){
	ans[v][u] = ans[u][v] = 1;
}
int construct(vector<vector<int>> P) {
	int n = sz(P);
	for (int i=0;i<n;i++){
		if(P[i][i] != 1)return 0;
		for(int j=0;j<n;j++){
			q[i][j] = ans[i][j] = 0;
			p[i][j] = P[i][j];
			if(p[i][j] == 3)return 0;
		}
	}
	//find all nodes connected to 1
	//then nodes with p(1,v) = 1
	//this has to form a tree
	//repeat forming many trees then link the trees in a cycle
	vector<int>ded(n,0);
	for(int v=0;v<n;v++){
		if(ded[v])continue;
		vector<int>comp;
		vector<bool>incomp(n,0);
		for(int j=0;j<n;j++){
			if(ded[j])continue;
			if(p[v][j]){
				incomp[j] = 1;
				comp.push_back(j);
				ded[j] = 1;
			}
		}
		for(int x:comp){
			for(int y:comp){
				if(!p[x][y])return 0;
			}
		}
		vector<vector<int>>trees;
		while(!comp.empty()){
			int v = comp[0];
			vector<int>tree,tmp;
			for(int u:comp){
				if(p[u][v] == 1)tree.push_back(u);
				else tmp.push_back(u);
			}
			trees.push_back(tree);
			comp = tmp;
		}
		int ss = sz(trees);
		if(ss==2)return 0;
		if(ss > 1)add(trees[0][0],trees[ss-1][0]);
		for(int i=0;i<ss;i++){
			if(i+1<sz(trees))add(trees[i][0],trees[i+1][0]);
			for(int j=0;j+1<sz(trees[i]);j++)add(trees[i][j],trees[i][j+1]);

			vector<bool>intree(n,0);
			for(int x:trees[i])intree[x] = 1;
			for(int x:trees[i]){
				for(int y:trees[i])q[x][y] = 1;
				for(int j=0;j<n;j++){
					if(incomp[j] && !intree[j])q[x][j] = q[j][x] = 2;
				}
			}
		}
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			if(q[i][j] != p[i][j])return 0;
		}
	}
	vector<vector<int>>fin(n);
	for(int i=0;i<n;i++){
		fin[i].assign(n,0);
		for(int j=0;j<n;j++)fin[i][j] = ans[i][j];
	}
	build(fin);
	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