Problem:
Score : 300 points

Problem Statement

A sequence a_1,a_2,... ,a_n is said to be /\/\/\/ when the following conditions are satisfied:

For each i = 1,2,..., n-2, a_i = a_{i+2}.

Exactly two different numbers appear in the sequence.

You are given a sequence v_1,v_2,...,v_n whose length is even.
We would like to make this sequence /\/\/\/ by replacing some of its elements.
Find the minimum number of elements that needs to be replaced.

Constraints

2 \leq n \leq 10^5

n is even.

1 \leq v_i \leq 10^5

v_i is an integer.

Input

Input is given from Standard Input in the following format:

n
v_1 v_2 ... v_n

Output

Print the minimum number of elements that needs to be replaced.

Sample Input 1

4
3 1 3 2

Sample Output 1

1

The sequence 3,1,3,2 is not /\/\/\/, but we can make it /\/\/\/ by replacing one of its elements: for example, replace the fourth element to make it 3,1,3,1.

Sample Input 2

6
105 119 105 119 105 119

Sample Output 2

0

The sequence 105,119,105,119,105,119 is /\/\/\/.

Sample Input 3

4
1 1 1 1

Sample Output 3

2

The elements of the sequence 1,1,1,1 are all the same, so it is not /\/\/\/.

Solution in Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)



import java.util.Scanner;

public class Main {

	static Scanner scanner;
	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

	    int N=gi();
	    int[] KV=new int[100001];
	    int[] GV=new int[100001];
	    int[] V= new int[N];

        for(int i=0; i<N;i++) {
        	int a=gi();
        	V[i]=a;
        	if((i+1)%2==1) {
        		KV[a]++;
        	} else {
        		GV[a]++;
        	}
        }

        int mki=0;
        int mgi=0;
        int mk=0;
        int mg=0;
        for(int i=0; i<100001;i++) {
        	int kv = KV[i];
        	int gv = GV[i];
        	if(mki<kv) {
        		mk=kv;
        		mki=i;
        	}
        	if(mgi<gv) {
        		mg=gv;
        		mgi=i;
        	}
        }

        long ans=0;
        if(mki==mgi) {
        	int mki2=0;
            int mgi2=0;
            int mk2=0;
            int mg2=0;
            for(int i=0; i<100001;i++) {
            	int kv = KV[i];
            	int gv = GV[i];
            	if(mki2<kv && mki!=i) {
            		mk2=kv;
            		mki2=i;
            	}
            	if(mgi2<gv && mgi!=i) {
            		mg2=gv;
            		mgi2=i;
            	}
            }
            if(mk2>mg2) {
            	ans=N-mk2-mg;
            } else {
            	ans=N-mk-mg2;
            }
		} else {
			ans = N-KV[mki] -GV[mgi];
		}


	    System.out.print(ans);
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
}