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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <algorithm>
#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <cstdio>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <set>

using namespace std;

int main(int argc, char *argv[])
{
  int n, ans = 1;
  long long a[200000], b[200000];
  cin >> n;

  cin >> a[0];
  for (int i = 1; i < n; i++) {
    cin >> a[i];
    b[i] = a[i] - a[i-1];
  }

  int prev = b[1];
  for (int i = 1; i < n; i++) {
    if (b[i-1]*b[i] < 0) {
      ans++;
      i++;
    }
  }

  printf("%d\n", ans);
  return 0;
}