Submission #336171

#	Time	Username	Problem	Language	Result	Execution time	Memory
336171		KWang31	Fun Tour (APIO20_fun)	Java	100 / 100	1463 ms	45820 KiB

fun

import java.util.*;
public class fun {
    public static class Pair implements Comparable<Pair>{
        int vtx; int val;
        public Pair(int a, int b){
            this.vtx=a; this.val=b;
        }
        public int compareTo(Pair other){
            if(this.val>other.val)return -1;
            if(this.val<other.val)return 1;
            if(this.vtx<other.vtx)return -1;
            return 1;
        }
    }
    public static int[] createFunTour(int N, int Q){
        if(N==2){
            int[] a=new int[2]; a[1]=1; return a;
        }
        int min=N; int ind=0; int sz=0;
        for (int i = 1; i < N; i++) {
            sz=grader.attractionsBehind(0,i);
            if(2*sz>=N && sz<min){
                min=sz; ind=i;
            }
            
        }
        int c=0;
        if(min!=N){
            c=ind;//Centroid
        }
        int[] ch=new int[3]; Arrays.fill(ch,-1);
        sz=0;
        for (int i = 0; i < N; i++) {
            if(i==c)continue;
            if(grader.hoursRequired(c,i)==1){
                ch[sz]=i; sz++;
            }
        }
        int x,y;
        
        ArrayList<Pair> arl[]=new ArrayList[3];
        for(int i=0;i<3;i++){arl[i]=new ArrayList<>(); if(i<sz){arl[i].add(new Pair(ch[i],1));}}
        
        if(sz==3){
            for (int i = 0; i < N; i++) {
                if(i==c || i==ch[0] || i==ch[1] || i==ch[2])continue;
                x=grader.hoursRequired(ch[0],i);
                y=grader.hoursRequired(ch[1],i);
                if(x<y){
                    arl[0].add(new Pair(i,x+1));
                }else if(y<x){
                    arl[1].add(new Pair(i,y+1));
                }else{
                    arl[2].add(new Pair(i,x-1));
                }
            }
        }else{
            for (int i = 0; i < N; i++) {
                if(i==c || i==ch[0] || i==ch[1])continue;
                x=grader.hoursRequired(ch[0],i);
                y=grader.hoursRequired(ch[1],i);
                if(x<y){
                    arl[0].add(new Pair(i,x+1));
                }else{
                    arl[1].add(new Pair(i,y+1));
                }
            }
        }
        
        int[] a=new int[N]; int[] b=new int[N];
        if(arl[0].size()==N/2){
            arl[1].add(new Pair(c,-1));
        }else{
            arl[0].add(new Pair(c,-1));
        }
        for(int i=0;i<3;i++){Collections.sort(arl[i]);}//Sort in descending order
        if(sz==2){
          int[] p=new int[2]; int cur=0;
          if(arl[1].size()>arl[0].size()){
             cur=1;
          }
          for(int done=0; done<N; done++){
             a[done]=arl[cur].get(p[cur]).vtx; p[cur]++; cur=1-cur;
          }
          return a;
        }
        int[] p=new int[3];//Keeps current pointer
        int z=0;
        
        int cur=0;//We cannot use vertices from the same subtree twice in a row
        x=arl[0].get(p[0]).val;  y=0;
        for(int i=1; i<3; i++){
          if(!arl[i].isEmpty() && arl[i].get(0).val >= x){
             x=arl[i].get(0).val; cur=i;
          }
        }
        //System.out.println(arl[0].size()+" "+cur);
        a[0]=arl[cur].get(p[cur]).vtx; p[cur]++;
        //System.out.println(a[0]+".."+cur);
        //System.out.println(Arrays.toString(p));
        for(int done=1; done<N; done++){
            if(p[(cur+1)%3]<arl[(cur+1)%3].size()){x=arl[(cur+1)%3].get(p[(cur+1)%3]).val;} else{x=-5;}
            if(p[(cur+2)%3]<arl[(cur+2)%3].size()){y=arl[(cur+2)%3].get(p[(cur+2)%3]).val;} else{y=-5;}
            if(x==-5 && y==-5){
               a[done]=arl[cur].get(p[cur]).vtx; return a;
            }else if(2*(arl[(cur+1)%3].size()-p[(cur+1)%3])>=N-done+1 && y<=b[done-1]){
              cur=(cur+1)%3;
            }else if(2*(arl[(cur+2)%3].size()-p[(cur+2)%3])>=N-done+1 && x<=b[done-1]){
              cur=(cur+2)%3;
            }else if(x>y){
              cur=(cur+1)%3;
              
            }else{
              cur=(cur+2)%3;
            }
            //System.out.println(done+" "+cur+" "+p[cur]);
            a[done]=arl[cur].get(p[cur]).vtx; 
            b[done]=arl[cur].get(p[cur]).val;
            p[cur]++;
        }
        
        return a;
    }
}

Compilation message (stderr)

Note: fun.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 21 / 21
• Subtask 4: 19 / 19
• Subtask 5: 34 / 34