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;
    class Program
    {
        static void Main(string[] args)
        {

            int a = int.Parse(Console.ReadLine()); //標準入力
            string[] str = Console.ReadLine().Split(' '); //2つ以上のスペース区切り入力の取得
            ulong[] A = new ulong[a];
            for (int j = 0; j < a; j++) {
                A[j] = ulong.Parse(str[j]);
                //Console.WriteLine("{0},{1}", a,A[j]);
            };
            int count = 0, flag = 0;

            if (a == 1 || a == 2)
            {
                Console.WriteLine("1");
                return;
            }



            for (int i = 1; i < a - 1; i++)
            {
                if (A[i]  > A[i - 1])
                {
                    flag = 1;
                }

                if (A[i]  < A[i - 1])
                {
                    flag = -1;
                }
                if (A[i] == A[i - 1]) continue;

                switch (flag)
                {
                    case 1:
                        if (A[i] > A[i + 1])
                        {
                            count++;
                            flag = -1;
                            i++;
                        };
                        continue;
                    case -1:
                        if (A[i] < A[i + 1])
                        {
                            count++;
                            flag = 1;
                            i++;
                        };
                        continue;
                    default:
                        continue;

                }

            }

            count++;

            Console.WriteLine("{0}", count);

            // Keep the console window open in debug mode.
            //Console.WriteLine("Press any key to exit.");
            Console.ReadKey();
            //int a = int.Parse(Console.ReadLine()); //標準入力
            //string[] str = Console.ReadLine().Split(' ');//2つ以上のスペース区切り入力の取得
            //int b = int.Parse(str[0]);  //数値で受け取りたい場合は変換する
            //int c = int.Parse(str[1]);
        }
    }