Submission #994828

#	Time	Username	Problem	Language	Result	Execution time	Memory
994828		Newtonabc	Connecting Supertrees (IOI20_supertrees)	C++14	56 / 100	133 ms	24148 KiB

supertrees

#include "supertrees.h"
#include<bits/stdc++.h>
using namespace std;
const int N=1e3+10;
vector<int> v;
int pa[N];
bool cy[N][N];
vector<int> adj[N];
bool vs[N];
void dfs(int u){
	vs[u]=true;
	if(adj[u].size()==1) v.push_back(u);
	for(int i=0;i<adj[u].size();i++){
		if(!vs[adj[u][i]]) dfs(adj[u][i]);
	}
}
int root(int x){
	if(pa[x]==x) return x;
	else return pa[x]=root(pa[x]);
}
int construct(vector<vector<int> > p) {
	int n = p.size();
	vector<vector<int> > answer;
	for (int i = 0; i < n; i++) {
		vector<int> row(n,0);
		answer.push_back(row);
	}
	for(int i=0;i<n;i++) pa[i]=i;
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			if(p[i][j]==1 && root(i)!=root(j)){
				answer[i][j]=1;
				answer[j][i]=1;
				pa[root(i)]=root(j);
			}
			if(p[i][j]==3) return 0;
		}
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			if(p[i][j]==0){
				if(root(i)==root(j)) return 0;
			}
		}
	}
	int cnt=0,cl=0;
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			int a,b;
			if(p[i][j]==2){
				a=root(i),b=root(j);
				if(a==b) continue;
				if(answer[a][b]==0) cnt++;
				pa[a]=b;
				answer[a][b]=1;
				answer[b][a]=1;
				adj[a].push_back(b);
				adj[b].push_back(a);
			}
		}
	}
	if(cnt==1) return 0;
	for(int i=0;i<n;i++){
		if(!vs[i]) dfs(i);
		if(v.empty()) continue;
		answer[v[0]][v[1]]=1;
		answer[v[1]][v[0]]=1;
		v.clear();
	}
	build(answer);
	return 1;
}

Compilation message (stderr)

supertrees.cpp: In function 'void dfs(int)':
supertrees.cpp:13:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |  for(int i=0;i<adj[u].size();i++){
      |              ~^~~~~~~~~~~~~~
supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:46:12: warning: unused variable 'cl' [-Wunused-variable]
   46 |  int cnt=0,cl=0;
      |            ^~

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