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 <cmath>
#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <iterator>      // std::next prev


using namespace std;


int main() {   
    std::ios::sync_with_stdio(false);
	int n;
	cin>>n;
	vector<int> nums;
	int a;
	cin>>a;
	nums.push_back(a);
	for(int i = 1 ; i < n ; i++)
	{
		int na;
		cin>>na;
		if(na==nums.back())
		{
			continue;
		}
		nums.push_back(na);
	}
	int ans = 1;
	for(int i = 1 ; i < nums.size()-1 ; )
	{
		if((nums[i-1]-nums[i])*(nums[i]-nums[i+1])<0)
		{
			ans++;
			i = i+2;
		}else
		{
			i++;
		}
	}
	cout<<ans;
	
	return 0;
}