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;

namespace AGC013_A
{
    class Program
    {
        static void Main(string[] args)
        {
            int amount = int.Parse(Console.ReadLine());
            int[] numbers = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();

            int split = 0;
            for (int i = 0; i < amount - 1; i++)
            {
                if (numbers[i] == numbers[i + 1])
                {
                    continue;
                }

                if (numbers[i] < numbers[i + 1])
                {
                    int a = i + 1;
                    while (a < amount - 1)
                    {
                        if (numbers[a] <= numbers[a + 1])
                        {
                            a++;
                        }
                        else
                        {
                            i += a - i;
                            break;
                        }
                    }
                    if (a == amount - 1)
                    {
                        break;
                    }
                    split++;
                }
                else if (numbers[i] > numbers[i + 1])
                {
                    int a = i + 1;
                    while (a < amount - 1)
                    {
                        if (numbers[a] >= numbers[a + 1])
                        {
                            a++;
                        }
                        else
                        {
                            i += a - i;
                            break;
                        }
                    }
                    if (a == amount - 1)
                    {
                        break;
                    }
                    split++;
                }
            }
            Console.WriteLine(split + 1);
        }
    }
}