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 <algorithm>
using namespace std;
int main(void){
    int n;
    cin>>n;
    int num1[n/2],num2[n/2];
    for(int i=0;i<n/2;i++){
        cin>>num1[i]>>num2[i];
    }
    int ans;
    if(n%4==0) {ans=n/4;}
    else ans=(n/2+1)/2;
    int a,b;
    int count1=0;
    int count2=0;
    for(int i=0;i<n/2;i++){a=num1[i]; count1=0;
        for(int j=0;j<n/2;j++){
            if(num1[j]==a) count1++;
        }
        if(count1>=ans) {count1=n/2-count1; break;}
    }
    for(int i=0;i<n/2;i++){b=num2[i]; count2=0;
    for(int j=0;j<n/2;j++){
        if(num2[j]==b) count2++;
    }
        if(count2>=ans) {count2=n/2-count2; break;}
    }
    if(count2==0&&count1==0&&num1[0]==num2[0]) cout<<n/2;
    else cout<<count2+count1;
    return 0;
}