Submission #301438

#TimeUsernameProblemLanguageResultExecution timeMemory
301438KWang31Connecting Supertrees (IOI20_supertrees)Java
100 / 100
536 ms59016 KiB
import java.io.*; import java.util.*;
public class supertrees {

    static class Pair implements Comparable<Pair>{
        int v; int l0;
        public Pair(int a, int b){
            this.v=a; this.l0=b;
        }
        public int compareTo(Pair other){//Sort by l0 values
            if(this.l0>other.l0)return 1;
            if(this.l0<other.l0)return -1;
            if(this.v<other.v)return -1;
            if(this.v>other.v)return 1;
            return 0;
        }
    }
    /*
    public static void main(String[] args) throws IOException {
        // Tester code
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        int N=Integer.parseInt(br.readLine());
        int[][] p=new int[N][N];
        for (int i = 0; i < N; i++) {
            StringTokenizer st=new StringTokenizer(br.readLine());
            for (int j = 0; j < N; j++) {
                p[i][j]=Integer.parseInt(st.nextToken());
            }
        }
        System.out.println(construct(p));
    }
*/
   public static int construct(int[][] p){
        int N=p.length;
        
        int[][] b=new int[N][N];
        int[] rank1=new int[N];//Consider the graph of 1-edges
        int[] rank0=new int[N];//Graph of 1,2-edges
        
        int[] par1=new int[N];
        int[] par0=new int[N];
        
        for (int i =0; i < N; i++) {
            par1[i]=i; par0[i]=i; 
        }
        int ii,jj;
        for (int i = 0; i < N; i++) {
            for (int j =0; j < N; j++) {
                if(i==j)continue;
                if(p[i][j]==1){
                    ii=find(i,par1); jj=find(j,par1);
                    if(ii!=jj){
                        if(rank1[ii]<rank1[jj]){
                            par1[ii]=jj;
                        }else if(rank1[ii]==rank1[jj]){
                            par1[ii]=jj; rank1[jj]++;
                        }else{
                            par1[jj]=ii;
                        }
                    }
                    ii=find(i,par0); jj=find(j,par0);
                    if(ii!=jj){
                        if(rank0[ii]<rank0[jj]){
                            par0[ii]=jj; 
                        }else if(rank0[ii]==rank0[jj]){
                            par0[ii]=jj; rank0[jj]++;
                        }else{
                            par0[jj]=ii;
                        }
                    }
                }else if(p[i][j]==2){
                    ii=find(i,par1); jj=find(j,par1);
                    if(ii==jj){//Deals with case i)
                        return 0;
                    }
                    
                    ii=find(i,par0); jj=find(j,par0);
                    if(ii!=jj){
                        if(rank0[ii]<rank0[jj]){
                            par0[ii]=jj;
                        }else if(rank0[ii]==rank0[jj]){
                            par0[ii]=jj; rank0[jj]++;
                        }else{
                            par0[jj]=ii;
                        }
                    }
                }else if(p[i][j]==3){
                    return 0;
                }else{
                    ii=find(i,par0); jj=find(j,par0);
                    if(ii==jj)return 0;
                }
            }
        }
        //Now for every 1-2 component, we need to find number of 1-leaders
        //That is the length of cycle. I lose if its length is 2 (length 1 is just a tree)
        boolean[] done=new boolean[N];
        int[] ans=new int[N];
        
        for (int i = 0; i < N; i++) {
            ii=find(i,par1);
            if(!done[ii]){
                jj=find(ii,par0);
                
               ans[jj]++;
                
                done[ii]=true;
            }
        }
         //System.out.println(Arrays.toString(ans));
        for (int i = 0; i < N; i++) {
            if(ans[i]==2){
                return 0;
            }
        }
        
        
        TreeSet<Pair> leads=new TreeSet<>();//Include leaders of all 1-components
        done=new boolean[N];
        for (int i = 0; i < N; i++) {//1-graphs
            
            ii=find(i,par1);
            if(ii!=i){
                b[i][ii]=1; b[ii][i]=1;
                
                //Same component guys don't matter
            }
            //I want to insert every root of each par1 component exactly once
            if(!done[ii]){
                leads.add(new Pair(ii,find(ii,par0)));
                
            }
            
        }
        
        int prevl=-1;
        //Completes a cycle for a component
        
        ArrayList<Integer> arl=new ArrayList<>();
        for (Pair q: leads) {
            //System.out.println(q.v+" "+q.l0+" "+prevv);
            //System.out.println(q.v+" "+q.l0);
            if(prevl!=q.l0){
                if(arl.size()>0){
                    for (int i = 0; i < arl.size()-1; i++) {
                        b[arl.get(i)][arl.get(i+1)]=1;
                        b[arl.get(i+1)][arl.get(i)]=1;
                    }
                    b[arl.get(0)][arl.get(arl.size()-1)]=1;
                    b[arl.get(arl.size()-1)][arl.get(0)]=1;
                    arl=new ArrayList<>();
                    
                }
            }
            arl.add(q.v);
            prevl=q.l0;
        }
       //  System.out.println(arl);
        if(arl.size()>0){
              for (int i = 0; i < arl.size()-1; i++) {
                   b[arl.get(i)][arl.get(i+1)]=1;
                   b[arl.get(i+1)][arl.get(i)]=1;
              }
              b[arl.get(0)][arl.get(arl.size()-1)]=1;
              b[arl.get(arl.size()-1)][arl.get(0)]=1;
                    
       }
        //Last fill
        //The leaders of every component forms a cycle as long as they're connected in the >=1 graph
        for (int i = 0; i < N; i++) {
           b[i][i]=0;
       }
        grader.build(b);
        
        
        return 1;
    }
    
    public static int find(int x, int[] par){
        if(par[x]==x)return x;
        int ans=find(par[x],par);
        par[x]=ans; return ans;
    }
}
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