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 Python (3.4.3) (judge verdict: Time Limit Exceeded)

N=int(input())
v=list(map(int,input().split()))

v1=v[::2]
V1=list(set(v1))
n1=len(V1)
v2=v[1::2]
V2=list(set(v2))
n2=len(V2)

cnt1={}
cnt2={}

for i in range(n1):
  cnt1[V1[i]]=v1.count(V1[i])
for i in range(n2):
  cnt2[V2[i]]=v2.count(V2[i])

max1_k=max(cnt1,key=cnt1.get)
max2_k=max(cnt2,key=cnt2.get)
if max1_k!=max2_k:
  print(N-cnt1[max1_k]-cnt2[max2_k])
else:
  if cnt1[max1_k]>=cnt2[max2_k]:
    if n2==1:
      print(N-cnt1[max1_k])
    else:
      cnt2.pop(max2_k)
      max2_k=max(cnt2,key=cnt2.get)
      print(N-cnt1[max1_k]-cnt2[max2_k])
  else:
    if n1==1:
      print(N-cnt2[max2_k])
    else:
      cnt1.pop(max1_k)
      max1_k=max(cnt1,key=cnt.get)
      print(N-cnt1[max1_k]-cnt2[max2_k])