Problem:
Score : 300 points

Problem Statement

You are given an array A of length N.
Your task is to divide it into several contiguous subarrays.
Here, all subarrays obtained must be sorted in either non-decreasing or non-increasing order.
At least how many subarrays do you need to divide A into?

Constraints

1 \leq N \leq 10^5

1 \leq A_i \leq 10^9

Each A_i is an integer.

Input

Input is given from Standard Input in the following format:

N
A_1 A_2 ... A_N

Output

Print the minimum possible number of subarrays after division of A.

Sample Input 1

6
1 2 3 2 2 1

Sample Output 1

2

One optimal solution is to divide the array into [1,2,3] and [2,2,1].

Sample Input 2

9
1 2 1 2 1 2 1 2 1

Sample Output 2

5

Sample Input 3

7
1 2 3 2 1 999999999 1000000000

Sample Output 3

3

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static void Main(string[] args)
    {
        Console.ReadLine();
        string[] arrStr = Console.ReadLine().Split(' ');
        List<int> lstInt = new List<int>();

        for(int i = 0; i < arrStr.Length; i++)
        {
            lstInt.Add(int.Parse(arrStr[i]));
        }

        int intSplit = 1;
        int intUpDownFlg = 0; // 1 ならUp, -1 ならDown

        for(int i = 1; i < lstInt.Count; i++)
        {
            switch (intUpDownFlg)
            {
                case 1:
                    if(lstInt[i - 1] > lstInt[i])
                    {
                        intSplit++;
                        intUpDownFlg = 0;
                    }
                    break;
                case -1:
                    if (lstInt[i - 1] < lstInt[i])
                    {
                        intSplit++;
                        intUpDownFlg = 0;
                    }
                    break;
                case 0:
                    if (lstInt[i - 1] > lstInt[i])
                    {
                        intUpDownFlg = -1;
                    }
                    if (lstInt[i - 1] < lstInt[i])
                    {
                        intUpDownFlg = 1;
                    }
                    break;
                default:
                    break;
            }
        }

        Console.WriteLine(intSplit.ToString());
    }
}