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.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in =  new Scanner(System.in);
		int n = in.nextInt();
		List<Integer> list = new ArrayList<>();

		for (int i = 0; i < n; i++) {
			list.add(in.nextInt());
		}
		in.close();


		int count = 1;
		int before = list.get(0);
		for (int i = 1; i < list.size(); i++) {
			int now = list.get(i);
			if(before + 1 == now) {
				before = now;
				for(i++; i < list.size(); i++) {
					now = list.get(i);
					if(!(before + 1 == now || before == now)) {
						count++;
						break;
					}
				}
				before = now;
			} else if(before - 1 == now) {
				before = now;
				for(i++; i < list.size(); i++) {
					now = list.get(i);
					if(!(before - 1 == now || before == now)) {
						count++;
						break;
					}
				}
				before = now;
			} else if(before == now) {
				continue;
			} else {
				count++;
			}
			before = now;
		}
		System.out.println(count);
	}

}