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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>

int main()
{
int n, i, even[2000000], odd[2000000], a[2000000], max_even=0, max_odd=0, value_even, value_odd;
scanf("%d", &n);
for(i=0;i<n;i++){
even[i]=0;
odd[i]=0;
}
for(i=0;i<n;i++){
scanf("%d", &a[i]);
if(i%2==0)even[a[i]]++;
else odd[a[i]]++;
}
while(1){
for(i=0;i<200000;i++){
if(max_even<=even[i]){
max_even=even[i];
value_even=i;
}
if(max_odd<=odd[i]){
max_odd=odd[i];
value_odd=i;
}
}
if(value_even!=value_odd)break;
else{
if(max_even<max_odd)odd[value_odd]=0;
else even[value_even]=0;
max_even=0;
max_odd=0;
value_even=0;
value_odd=0;
}
}
int k=n-max_odd-max_even;
printf("%d\n", k);
return 0;
}