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: Runtime Error)

using System;

namespace agc013_a
{
    class Program
    {
        static void Main()
        {
            int n = int.Parse(Console.ReadLine());
            string[] s = Console.ReadLine().Split();
            int[] x = new int[n];
            for (int i = 0; i < n; i++)
            {
                x[i] = int.Parse(s[i]);
            }
            int ret = 0;
            bool up = x[1] - x[0] >= 0;
            for (int i = 2; i < n; i++)
            {
                if ((up == true && x[i] - x[i - 1] < 0 == true) || (up == false && x[i] - x[i - 1] > 0 == true))
                {
                    ret++;
                    i++;
                    if (i >= n)
                    {
                        break;
                    }
                    while (x[i] == x[i - 1])
                    {
                        if (i >= n)
                        {
                            break;
                        }
                        i++;
                    }
                    if (i >= n)
                    {
                        break;
                    }
                    up = x[i] - x[i - 1] >= 0;
                }
            }
            Console.WriteLine(ret + 1);
            //Console.ReadLine();
        }
    }
}