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)

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define REP(i,a,b) for (int i = a; i < (b); ++i)
#define all(x) (x).begin(),(x).end()
#define YY cout << "Yes" << endl;
#define NN cout << "No" << endl;
const int INF = 1000000007;
typedef long long ll;
using namespace std;
using Graph = vector<vector<int>>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
ll lcm(ll a, ll b) { return (a * b) / gcd(a,b); }
int solve(){
  int n;
  cin >> n;
  vector<int>v(n);
  map<int,int>a,b;
  rep(i,n)cin >> v[i];
  rep(i,n){
    if(i%2)a[v[i]]++;
    else b[v[i]]++;
  }
  int a_cnt = -1,b_cnt = -1,a_num = -1,b_num = -1;
  for(auto i : a){
    if(i.second > a_cnt){
      a_cnt = i.second;
      a_num = i.first;
    }
  }
  for(auto i : b){
    if(i.second > b_cnt){
      b_cnt = i.second;
      b_num = i.first;
    }
  }
  if(a_num != b_num){
    cout << (n / 2) - a_cnt + (n / 2) - b_cnt;
    return 0;
  }
  ll ans = 0;
  int tmp_cnt = -1,tmp_num = - 1;
  for(auto i : a){
    if(i.second > a_cnt && i.first != a_num){
      tmp_cnt = i.second;
      tmp_num = i.first;
    }
  }
  if(tmp_num == -1)tmp_cnt = 0;
  ans = (n / 2) - tmp_cnt + (n / 2) - b_cnt;
  tmp_cnt = -1,tmp_num = - 1;
  for(auto i : b){
    if(i.second > a_cnt && i.first != a_num){
      tmp_cnt = i.second;
      tmp_num = i.first;
    }
  }
  if(tmp_num == -1)tmp_cnt = 0;
  ans = max(ans,(ll)(n / 2) - a_cnt + (n / 2) - tmp_cnt);
  cout << ans << endl;
  return 0;
}
int main(){
  // ios::sync_with_stdio(false);cin.tie(nullptr);
  // cout << fixed;cout << setprecision(16) << endl; 
  solve();
  return 0;
}