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"
	"math"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var out = bufio.NewWriter(os.Stdout)

func main() {
	/*/TODO:!!!!!!!テスト用!!!!!!!!!
	sc = bufio.NewScanner(strings.NewReader(`

						`))
	//TODO:!!!!!!!テスト用!!!!!!!!!*/

	buf := make([]byte, 1024*1024)
	sc.Buffer(buf, bufio.MaxScanTokenSize)
	sc.Split(bufio.ScanWords)
	defer out.Flush() // !!!!caution!!!! you must use Fprint(out, ) not Print()
	/* --- code --- */
	//fmt.Fprintln(out, "[DEBUG]", time.Now())

	n := nextInt()
	ans := 1

	b := nextInt()
	f := 0

	for i := 1; i < n; i++ {
		a := nextInt()
		if (f == -1 && b >= a) || (f == 1 && b <= a) {
		} else if f == 0 {
			if b > a {
				f = -1
			} else if b < a {
				f = 1
			}
		} else {
			f = 0
			ans++
		}
		b = a
	}

	//fmt.Fprintln(out, "[DEBUG]]", a)
	fmt.Fprintln(out, ans)
}

//------------------------------------------------------------------------------

// -*-*-*-*-*-*-*-*-
// * I/O utilities *
// -*-*-*-*-*-*-*-*-

func next() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	a, _ := strconv.Atoi(next())
	return a
}

func nextFloat64() float64 {
	a, _ := strconv.ParseFloat(next(), 64)
	return a
}

func nextInts(n int) []int {
	ret := make([]int, n)
	for i := 0; i < n; i++ {
		ret[i] = nextInt()
	}
	return ret
}
func nextFloats(n int) []float64 {
	ret := make([]float64, n)
	for i := 0; i < n; i++ {
		ret[i] = nextFloat64()
	}
	return ret
}
func nextStrings(n int) []string {
	ret := make([]string, n)
	for i := 0; i < n; i++ {
		ret[i] = next()
	}
	return ret
}

func chars(s string) []string {
	ret := make([]string, len([]rune(s)))
	for i, v := range []rune(s) {
		ret[i] = string(v)
	}
	return ret
}

func absInt(x int) int {
	return int(math.Abs(float64(x)))
}
func minInt(x, y int) int {
	if x < y {
		return x
	}
	return y
}
func maxInt(x, y int) int {
	if x > y {
		return x
	}
	return y
}
func log10(x int) float64 {
	return math.Log10(float64(x))
}