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;

namespace AGC013A
{
    class Program
    {
        static void Main(string[] args)
        {
            int N = int.Parse(Console.ReadLine());
            var target = Console.ReadLine().Split(' ');
            var a = new List<int>();
            for(int i=0;i<N;i++){
               a.Add(int.Parse(target[i]));
            }
            int p1 = 0; int count = 1;
            int p2 = 1;
            bool up = false;
            bool down = false;
            while(p2 < a.Count ){
                if(a[p1] == a[p2]) {p1++;p2++; continue;}
                if(up){
                    if(a[p1] > a[p2]){
                        up = false; down = false;
                        count++; p1 = p2;p2++; continue;
                    } else {
                        p1++;p2++; continue;
                    }
                } else if(down){
                    if(a[p1] < a[p2]){
                        up = false; down = false;
                        count++; p1 = p2; continue;
                    } else {
                        p1++;p2++; continue;
                    }
                } else {
                    if(a[p1] > a[p2]) {down = true; p1++;p2++; continue;}
                    if(a[p1] < a[p2]) {up = true; p1++;p2++; continue;}
                }
            }
            Console.WriteLine(count);
        }
    }
}