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: Wrong Answer)

import java.io.IOException;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Scanner;

class Main {
	public static void main(String[] args) throws IOException {
		new Main().run();
	}

	void run() throws IOException {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] A = new int[n];
		for (int i = 0; i < n; ++i) {
			A[i] = sc.nextInt();
		}

		ArrayDeque<Integer> que = new ArrayDeque<>();
		for (int a : A) {
			que.addLast(a);
		}

		int cnt = 0;
		ArrayList<Integer> cur = new ArrayList<>();
		while (!que.isEmpty()) {
			int v = que.pollFirst();
			if (cur.size() < 2) {
				if (cur.size() == 0)
					++cnt;
				cur.add(v);
				continue;
			}

			if ((long) (cur.get(cur.size() - 1) - cur.get(cur.size() - 2))
					* (long) (v - cur.get(cur.size() - 1)) >= 0) {
				cur.add(v);
			} else {
				cur.clear();
				cur.add(v);
				++cnt;
			}
		}
		System.out.println(cnt);

	}
}