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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;

public class Main {

    public static void main(String args[]) {

        // 入力
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        Integer[] a = new Integer[n];
        Arrays.setAll(a, i -> Integer.parseInt(sc.next()));
        sc.close();

        // 主処理
        int count = 1;
        Boolean isIncrease = null;
        for (int i = 1; i < n - 1; i++) {
            int left = a[i - 1];
            int right = a[i + 1];
            int center = a[i];

            if (isIncrease == null) {
                isIncrease = left == center ? null : left < center;
            }

            if (isIncrease != null) {
                if (isIncrease && right < center) {
                    count++;
                    isIncrease = null;
                    i++;

                } else if (!isIncrease && center < right) {
                    count++;
                    isIncrease = null;
                    i++;

                }
            }
        }
        int result = count;

        // 出力
        System.out.println(result);
    }
}