July long challenge (chefina & swaps , ada king & missing a point) video Editorials

editorial
1

Hello codechef community , this is CodeNCode

Here are the video editorials.

Beside these video I have course teaching many concepts free of any cost.
Some of them are

And many more.

Thanks for your valuable time.
CodeNCode out.

9 Likes
2

always on time

3

tum bahut mast kaam karta hai @waqar_ahmad224 bhai, from your lectures i learn Basic graph theory bas ab contest me questions hone lag jaaye I will surely contribute :v:

1 Like
4

yup :slight_smile:

1 Like
5

do one for Doctor chef As well…this has bugged me a lot

6

haha thanks man.
and don’t worry about contribution just focus on your learning.

2 Likes
7

Dil jeet liya bhai :hugs:

2 Likes
8

thanks again brother.

2 Likes
9

a bit busy but will work on that for sure.

1 Like
10

same story.

11

must be a difficult problem then

12

thank you so much

13

okay…no problem… :slight_smile:

14

you’re welcome

15

:+1: .

16 
/* package codechef; // don't place package name! */
//package p1;
import java.util.*;
//import java.lang.*;
//import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Codechef
{
    	 public static boolean EvenFrequency(List<Long> a ,List<Long> b  ){
	        Map <Long,Integer> h = new HashMap<Long,Integer>();
	        for(int i=0;i<a.size();i++){
	            if(h.containsKey(a.get(i)))
	            h.put(a.get(i),h.get(a.get(i))+1);
	            else 
	            h.put(a.get(i),1);
	            if(h.containsKey(b.get(i)))
	            h.put(b.get(i),h.get(b.get(i))+1);
	            else 
	            h.put(b.get(i),1);
	        }
	        for(int i=0;i<a.size();i++){
	        if(h.get(a.get(i))%2!=0)
	        return false;
	        if(h.get(b.get(i))%2!=0)
	        return false;
	        }
	        return true;
	    }
	 public static void main(String args[]) {

	    	Scanner input = new Scanner(System.in);
		     int t = input.nextInt();
		     int n;
		     long value,min,subMin;
		     while(t-->0){
		         n = input.nextInt();
		         long a [] = new long[n];
		         long b [] = new long[n];
		         for(int i=0;i<n;i++) a[i] = input.nextLong();
		         for(int i=0;i<n;i++) b[i] = input.nextLong();
		         Arrays.sort(a);
		         Arrays.sort(b);
		         for(int j=0,i=0;j<a.length&&i<a.length;){
                             if(a[i]==b[j]){
                                   a[i++]=0;
                                   b[j++]=0;
                            }
                           else if(a[i]>b[j]) j++;
                          else i++;
                }
		      List <Long>  la = new ArrayList<>();
		      List <Long>  lb = new ArrayList<>();
		      for(int i=0;i<n;i++) {if(a[i]!=0) la.add(a[i]); if(b[i]!=0) lb.add(b[i]);}
		      if(la.size()==0&&lb.size()==0)   System.out.println("0");
		      else if(!Codechef.EvenFrequency(la,lb))
		      System.out.println("-1");
		      else{
		          value=0;
		          subMin = la.get(0)<=lb.get(0)?la.get(0):lb.get(0);
		          List<Long> lla = new ArrayList<>();
		          List<Long> llb = new ArrayList<>();
		          for(int i=0;i<la.size();i+=2){
		              lla.add(la.get(i));
		              llb.add(lb.get(i));
		          }
		          for(int i=0;i<lla.size();i++) {
		        	min = lla.get(i)<=llb.get(llb.size()-i-1)?lla.get(i):llb.get(llb.size()-i-1);
		        	if(min<2*subMin)
		        	value+=min;
		        	else
		        		value+=(2*subMin);
		         }
		          System.out.println(value);
		      }
		}
		     input.close();
	 }
}