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 N = parseInt(input.split("\n")[0]);
  var inputList = input.split("\n")[1].split(" ");
  var outputList = {};
  var useList = [];
  var output = 0;
  for(var i = 0; i < inputList.length; i++){
    if(outputList[inputList[i]] == null){
       outputList[inputList[i]] = 1;
      useList.push(inputList[i]);
       }else{
         outputList[inputList[i]]++;
       }
  }
  if(useList.length == 1){
     console.log(N/2);
     return;
  }else if(useList.length == 2){
    useList.sort(function(a,b){
    	return outputList[b] - outputList[a];
    });
     if(outputList[useList[0]] == outputList[useList[1]]){
       console.log("0");
     }else{
       console.log((outputList[useList[0]] - outputList[useList[1]]) / 2);
     }
  }else{
    useList.sort(function(a,b){
    	return outputList[b] - outputList[a];
    });
    useList.shift();
    useList.shift();
    for(var i = 0; i < useList.length; i++){
      output += outputList[useList[i]];
    }
    console.log(output);
  }
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));