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<bits/stdc++.h>
using namespace std;

  
int main(){
 
 int n;
 cin>>n;
 int a[n];
 for(int i=0;i<n;i++){
     cin>>a[i];
 }
 int c=1;
 for(int i=1;i<n;i++){
     if(a[0]==a[i]) c++; 
 }
 if(c==n) {
     cout<<"0";
     return 0;
 }
 map<int,int> m;
 for(int i=0;i<n;i=i+2){
     m[a[i]]++;
 }
 int maxi1=INT_MIN;
 int sec1=INT_MIN;
 int num1;
 for(auto i=m.begin();i!=m.end();i++){
     if(maxi1<i->second){
         num1=i->first ;
         sec1=maxi1;
         maxi1= i->second;
         
     }
     if(i->second > sec1){
         sec1= i->second;
     }
 }

 
 m.clear();
  for(int i=1;i<n;i=i+2){
     m[a[i]]++;
 }
 int  maxi2=INT_MIN;
  int num2;
  int sec2=INT_MIN;
 for(auto i=m.begin();i!=m.end();i++){
     if(maxi2<i->second){
         num2=i->first;
         sec2=maxi2;
         maxi2= i->second;
     }
     if(i->second > sec2){
         sec2= i->second;
     }
 }
 
 int res1= n-(sec2+maxi1);
 int res2= n-(sec1+maxi2);
 cout<<min(res1,res2);
 
 return 0;
}