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 <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <unordered_map>
#include <cstring>
#include <queue>
#include <map>
using namespace std;
typedef long long ll;
const int maxn = 100005;

int n,a[maxn];

int sgn(int x){
  return x<0?-1:(x==0?0:1);
}

int main() {
 // freopen("in.cpp","r",stdin);
  cin>>n;
  int ret=0;
  for(int i=0; i<n; i++)cin>>a[i];
  for(int i=0; i<n; i++) {
    int d=0;
    int k=i;
    for(int j=i+1;j<n;j++){
      if(a[j]!=a[j-1]){
        if(d==0)d=sgn(a[j]-a[j-1]);
        else if(d!=sgn(a[j]-a[j-1])){
          break;
        }
      }
      k=j;
    }
    ret++;
    i=k;
  }
  cout<<ret<<endl;
  return 0;
}