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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func main() {
	sc.Split(bufio.ScanWords)
	n := nextInt()
	slice := make([]int, n)

	for i := 0; i < n; i++ {
		slice[i] = nextInt()
	}

	length := 1
	up := 0
	down := 0

	for i := 1; i < len(slice); i++ {
		if slice[i-1] < slice[i] {
			up = 1
		} else if slice[i-1] > slice[i] {
			down = 1
		} else {
			// i++
			continue
		}

		if up == 1 && down == 1 {
			up = 0
			down = 0

			length++
		}

	}

	fmt.Println(length)

	// for i := 0; i < len(slice); i++ {
	// 	// tmp := slice[start:len(slice)]
	// 	// fmt.Println(slice)

	// 	for j := 1; j < len(slice)-1; j++ {
	// 		// fmt.Printf("i=%d, j=%d\n", i, j)
	// 		if j+1 < n && slice[i] <= slice[j] {
	// 			continue
	// 		}

	// 		if j+1 < n && slice[i] >= slice[j] {
	// 			length++
	// 			i += j
	// 			break
	// 		}

	// 		if j+1 < n && slice[i] > slice[j] && slice[j] > slice[j+1] {
	// 			continue
	// 		}

	// 		if j+1 < n && slice[i] < slice[j] && slice[j] > slice[j+1] {
	// 			length++
	// 			i += j
	// 			break
	// 		}

	// 		if j+1 < n && slice[i] == slice[j] && slice[j] == slice[j+1] {
	// 			continue
	// 		}

	// 	}
	// fmt.Println(length)

	// }

	// fmt.Println(length)

}