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: Wrong Answer)

import java.util.*;
 
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        int[] v = new int[n];
        Map<Integer, Integer> ki = new HashMap<>();
        Map<Integer, Integer> gu = new HashMap<>();
        for(int i=0; i<n; i++) {
            v[i] = Integer.parseInt(sc.next());
            if(i % 2 == 1) {
                if(ki.containsKey(v[i])) ki.put(v[i], ki.get(v[i])+1);
                else ki.put(v[i], 1);
            }else {
                if(gu.containsKey(v[i])) gu.put(v[i], gu.get(v[i])+1);
                else gu.put(v[i], 1);
            }
        }
        ki.put(0, 0);
        gu.put(0, 0);
        int kimax = 0;
        int gumax = 0;
        int kisemax = 0;
        int gusemax = 0;
        for(int key : ki.keySet()) {
            if(kimax < ki.get(key)) kimax = key;
        }
        for(int key : ki.keySet()) {
            if(key == kimax) continue;
            if(kisemax < ki.get(key)) kisemax = key;
        }
        for(int key : gu.keySet()) {
            if(gumax < gu.get(key)) gumax = key;
        }
        for(int key : gu.keySet()) {
            if(key == gumax) continue;
            if(gumax < gu.get(key)) gusemax = key;
        }
        if(kimax == gumax) System.out.println(n - max(ki.get(kimax)+gu.get(gusemax), ki.get(kisemax)+gu.get(gumax)));
        else System.out.println(n - ki.get(kimax) - gu.get(gumax));
        
    }
    public static int min(int a, int b) {
        if(a <= b) return a;
        else return b;
    }
    public static int max(int a, int b) {
        if(a <= b) return b;
        else return a;
    }
}