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: Accepted)

#include <bits/stdc++.h>

#define mp make_pair
#define pb push_back

using namespace std;

typedef int32_t i32;
typedef uint32_t u32;
typedef int64_t i64;
typedef uint64_t u64;
typedef pair<int,int> pii;
typedef vector<int> vi;

const int MAX_N = 100000;
int n;
int a[MAX_N];

int main()
{
  cin >> n;
  for (int i = 0; i < n; i++)
    cin >> a[i];

  n = unique(a, a+n) - a;

  int c = 0; bool in = true;
  for (int i = 1; i < n-1; i++)
    if (in && ((a[i-1] < a[i] && a[i] > a[i+1]) || (a[i-1] > a[i] && a[i] < a[i+1]))) {
        c++;
        in = false;
    } else {
      in = true;
    }

  cout << c + 1 << endl;

  return 0;
}