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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)


#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <map>

using namespace std;


int main()
{

	int N;

	cin >> N;

	map<int, int> Os, Es;
	int max_o = 0;
	int max_e = 0;
	int on, en;

	int n;
	for (int ni = 0; ni < N; ni++) {
		cin >> n;
		if (ni % 2 == 0) {
			if (Es.count(n) == 0) {
				Es[n] = 1;
			}
			else {
				Es[n]++;
			}
			if (Es[n] > max_e) {
				max_e = Es[n];
				en = n;
			}
		}
		else {
			if (Os.count(n) == 0) {
				Os[n] = 1;
			}
			else {
				Os[n]++;
			}
			if (Os[n] > max_o) {
				max_o = Os[n];
				on = n;
			}
		}
	}

	if (en == on) {
		cout << N / 2;
		return 0;
	}

	int ans = N / 2 - en + N / 2 - on;
	cout << ans;


	return 0;
}