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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
import java.io.*;
public class Main {
    public static void main(String[] args) throws Exception {
        InputStreamReader r = new InputStreamReader(System.in);
        int n = nextInt(r);

        int[] A = new int[n/2];
        int[] Ac = new int[n/2];
        int[] B = new int[n/2];
        int[] Bc = new int[n/2];
        for (int i = 0; i < n/2; i++) {
            A[i] = nextInt(r);
            count(A, Ac, i);
            B[i] = nextInt(r);
            count(B, Bc, i);
        }

        int Afi = 0;
        int Asi = 0;
        int Bfi = 0;
        int Bsi = 0;
        if (n > 2) {
            if (Ac[1] > Ac[0]) {
                Afi = 1;
            } else {
                Asi = 1;
            }

            if (Bc[1] > Bc[0]) {
                Bfi = 1;
            } else {
                Bsi = 1;
            }
        }

        for (int i = 2; i < n/2; i++) {
            if (Ac[i] > Ac[Afi]) {
                Asi = Afi;
                Afi = i;
            } else if (Ac[i] > Ac[Asi]) {
                Asi = i;
            }

            if (Bc[i] > Bc[Bfi]) {
                Bsi = Bfi;
                Bfi = i;
            } else if (Bc[i] > Bc[Bsi]) {
                Bsi = i;
            }
        }

        int d = 0;
        if (A[Afi] == B[Bfi] && Asi == 0 && Bsi == 0) {
            d = n/2;
        } else if (A[Afi] == B[Bfi] && Ac[Asi] == 0 && Bc[Bsi] == 0) {
            d = n/2;
        } else if (A[Afi] == B[Bfi]) {
            d = Ac[Asi] > Bc[Bsi] ? Ac[Asi] + Bc[Bfi] : Ac[Afi] + Bc[Bsi];
        } else {
            d = Ac[Afi] + Bc[Bfi];
        }
        System.out.println(n-d);
    }

    public static int nextInt(InputStreamReader r) throws Exception {
        String str = "";
        while (true) {
            int c = r.read();
            if (c == 32 || c == 10 || c == -1) {
                break;
            }
            str += (char)c;
        }
        return Integer.parseInt(str);
    }

    public static void sort(int[] T, int i) {
        for (int j = i; j > 0; j--) {
            if (T[j] > T[j-1]) {
                int tmp = T[j-1];
                T[j-1] = T[j];
                T[j] = tmp;
            } else {
                break;
            }
        }
    }

    public static void count(int[] T, int[] C, int i) {
        for (int j = 0; j < i; j++) {
            if (T[j] == T[i]) {
                C[j]++;
                return;
            }
        }
        C[i]++;
    }
}