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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function Main(input) {
  var data = input.split("\n")
  // var n = parseInt(data[0])
  var v = data[1].split(' ').map(function(vd) {
    return parseInt(vd)
  })
  var c = 0;
  
  var object1 = {}
  for (var i = 0; i < v.length; i = i + 2) {
    if (!object1[v[i]]) {
      object1[v[i]] = 0
    }
    object1[v[i]]++
  }

  var m0 = null
  var m0max = null
  for (var k in object1) {
    if (m0 === null) {
      m0 = k
      m0max = object1[k]
    }

    if (object1[k] > m0max) {
      m0 = k
      m0max = object1[k]
    }
  }

  var object2 = {}
  for (var i = 1; i < v.length; i = i + 2) {
    if (!object2[v[i]]) {
      object2[v[i]] = 0
    }
    object2[v[i]]++
  }

  var m1 = null
  var m1max = null
  for (var k in object2) {
    if (m1 === null) {
      m1 = k
      m1max = object2[k]
    }
    
    if (object2[k] > m1max) {
      m1 = k
      m1max = object2[k]
    }
  }

  for (var i = 0; i < v.length; i = i + 2) {
    if (m0 != v[i]) {
      c++;
    }
  }

  for (var i = 1; i < v.length; i = i + 2) {
    if (m1 != v[i]) {
      c++;
    }
  }

  if (c === 0) {
    if (v[0] === v[1]) {
      c = v.length / 2
    }
  }

  console.log(c);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));