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.Linq;
using System.Collections.Generic;

namespace Algorithm
{
    class Program
    {
        static void Main(string[] args)
        {
            var N = int.Parse(Console.ReadLine());
            var A = Console.ReadLine().Split().Select(int.Parse).ToArray();

            if (N == 1)
            {
                Console.WriteLine(1);
                return;
            }

            var total = 0;
            var up = 0;
            for (var i = 1; i < N; i++)
            {
                if (A[i] == A[i - 1]) continue;
                else if (A[i] > A[i - 1])
                {
                    if (up == 0) up = 1;
                    else if (up == 2)
                    {
                        up = 0;
                        total++;
                    }
                }
                else
                {
                    if (up == 0) up = 2;
                    else if (up == 1)
                    {
                        up = 0;
                        total++;
                    }
                }
            }

            Console.WriteLine(total + 1);
        }
    }
}