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 Rust (1.15.1) (judge verdict: Accepted)

use std::str::FromStr;
use std::fmt::Debug;
use std::cmp;
#[allow(dead_code)]
fn read_as_vec<T>() -> Vec<T>
where T: FromStr, <T as FromStr>::Err : Debug{
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().split_whitespace().map(|c| T::from_str(c).unwrap()).collect()

}

#[allow(dead_code)]
fn read_as_string() -> String{
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

fn main(){
    let n = read_as_vec::<usize>()[0];
    let mut a = read_as_vec::<u64>();
    a.dedup();
    let n = a.len();

    if n < 3{
        println!("1");
        return;
    }

    let mut i:usize = 0;
    let mut ans = 0;

    while i < n-1{
        let tmp = i;
        while i < n-1 && a[i] < a[i+1]{
            i += 1;
        }
        if tmp < i{
            ans += 1;
            i += 1;
        }
        let tmp = i;
        if i == n - 1 && a[n-2] > a[n-1]{
            ans += 1;
        }
        while i < n-1 && a[i] > a[i+1]{
            i += 1;
        }
        if tmp < i{
            ans += 1;
            i += 1;
        }
        if i == n - 1 && a[n-2] < a[n-1]{
            ans += 1;
        }
    }

    println!("{}", ans);
}