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.Collections.Generic;
using static System.Console;

class Program {
    static void Main() {
        var n = NextInt();
        var way = 0;
        var pre = 0;
        var ans = 1;

        for (var i = 0; i < n; i++) {
            var now = NextInt();
            if (i == 0 || now - pre == 0) {
                //pass
            } else if (way == 0) {
                way = Math.Sign(now - pre);
            } else if (Math.Sign(now - pre) != way) {
                ans++;
                way = 0;
            }
            pre = now;
        }
        WriteLine(ans);
    }

    static int NextInt() {
        return int.Parse(NextString());
    }

    static string NextString() {
        var result = new List<char>();
        while (true) {
            int next = Read();
            if (next < 0)
                break;
            var nextChar = (char)next;
            if (!char.IsWhiteSpace(nextChar))
                result.Add(nextChar);
            else if (nextChar != '\r')
                break;
        }
        return string.Join("", result);
    }
}