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 JavaScript (node.js v5.12) (judge verdict: Accepted)

// ※AtCoderでの提出の為、ES6で記述出来ません。

// 完成
(function(stdin){
  var input = stdin.split("\n");
  // 10進数に変換
  var n = parseInt(input[0], 10);
  var a = input[1].split(" ");

  for (var i = 0; i < n; i++) {
    a[i] = parseInt(a[i], 10);
  }

  var ans = 0;
  var up = false;
  var down = false;
  for (var i = 0; i < n - 1; i++) {
    if (a[i] < a[i + 1]) {
      up = true;
    }
 
    if (a[i] > a[i + 1]) {
      down = true;
    }
 
    if (up && down) {
      up = down = false;
      ans++;
    }
  }

  console.log(ans + 1);
})(require("fs").readFileSync("/dev/stdin", "utf8"));