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  1. import java.util.*;
  2. import java.lang.*;
  3. import java.io.*;
  4.  
  5. class Codechef{
  6.     public static void main (String[] args) throws java.lang.Exception
  7.     {
  8.         Scanner sc=new Scanner(System.in);
  9.         int n=sc.nextInt();
  10.         int a[]=new int[n];
  11.         int b[]=new int[n];
  12.         for(int i=0;i<n;i++)a[i]=sc.nextInt();
  13.         for(int i=0;i<n;i++)b[i]=sc.nextInt();
  14.         int ans=solve(n,a,b);
  15.         System.out.println(ans);
  16.     }
  17.  
  18.     public static int solve(int n,int[]a,int[]b){
  19.         HashMap<Integer,Integer>badBond=new HashMap<>();
  20.         int g=0;
  21.         for(int i=0;i<n;i++){
  22.             if(a[i]==b[i]){
  23.                 badBond.put(a[i],badBond.getOrDefault(a[i],0)+1);
  24.             }else{
  25.                 g++;
  26.             }
  27.         }
  28.         if (badBond.size()==0)return 0;
  29.         PriorityQueue<int[]>p=new PriorityQueue<>((r,s)->s[1]-r[1]);
  30.         for (var v:badBond.entrySet()) {
  31.             p.add(new int[]{v.getKey(),v.getValue()});
  32.         }
  33.         int swap=0;
  34.         while(p.size()>=2){
  35.             int[]x=p.poll();
  36.             int[]y=p.poll();
  37.             x[1]--;y[1]--;
  38.             swap++;
  39.             if (x[1]>0)p.add(x);
  40.             if (y[1]>0)p.add(y);
  41.         }
  42.         if (p.isEmpty())return swap;
  43.         int[]l=p.poll();
  44.         int left=l[1],val=l[0],goodB=0;
  45.         for(int i=0;i<n;i++){
  46.             if(a[i]!=b[i]){
  47.                 if(a[i]!=val&&b[i]!=val){
  48.                     goodB++;
  49.                 }
  50.             }
  51.         }
  52.         if (goodB<left)return -1;
  53.         swap+=left;
  54.         return swap;
  55.     }
  56. }
Success #stdin #stdout 0.17s 54584KB
comments (?)
stdin 
5
1 2 1 1 3
1 2 3 1 3
stdout 
2
https://ideone.com/4ytHut
language:
Java (HotSpot 12)
created:
1 day ago
visibility:
public

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