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: Wrong Answer)

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

namespace AGC013
{
    public class A
    {
        private int F(int[] A, bool up)
        {
            int result = 0;
            bool first = true;
            int last = 0;
            foreach (var a in A)
            {
                if (first)
                {
                    result++;
                    last = a;
                }
                else
                {
                    if (up)
                    {
                        if (last < a)
                        {
                            result++;
                            up ^= true;
                        }
                    }
                    else
                    {
                        if (last > a)
                        {
                            result++;
                            up ^= true;
                        }
                    }
                }
                first = false;
                last = a;
            }
            return result;
        }
        private void Run()
        {
            Console.ReadLine();
            var A = Console.ReadLine().Trim().Split().Select(int.Parse).ToArray();
            Console.WriteLine(Math.Min(F(A, true), F(A, false)));
        }

        public static void Main()
        {
            var old = Console.Out;
            using (var writer = new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false })
            {
                Console.SetOut(writer);
                new A().Run();
                Console.Out.Flush();
                Console.SetOut(old);
            }
        }
    }
}