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)

import math
import copy
import sys
import fractions
import numpy as np
from functools import reduce

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum

def getInputListInt():
    outputoData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData

def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList

def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList

# ===CODE===

n, = map(int, input().split())
data = getInputListInt()

param = []
tmpparam = []
onelist = []
twolist = []

tmp = 0
for i in range(n):
    if tmpparam.count(data[i]) == 0:
        param.append([data[i], 0, 0])
        tmpparam.append(data[i])

if len(param)==1:
    param.append([0, 0, 0])

for i in range(len(param)):
    for j in range(n):
        if j%2==0:
            if data[j]!=param[i][0]:
                param[i][1]+=1
        else:
            if data[j]!=param[i][0]:
                param[i][2]+=1

srtlist = sorted(param, key=lambda x:x[1])
onemin1 = [srtlist[0][0], srtlist[0][1]]
onemin2 = [srtlist[1][0], srtlist[1][1]]

srtlist = sorted(param, key=lambda x:x[2])
twomin1 = [srtlist[0][0], srtlist[0][2]]
twomin2 = [srtlist[1][0], srtlist[1][2]]

if onemin1[0] != twomin1[0]:
    print(onemin1[1]+twomin1[1])
else:
    print(min(onemin1[1]+twomin2[1], onemin2[1]+twomin1[1]))