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 (GCC 9.2.1) (judge verdict: Accepted)

#include <stdio.h>
#define rep(i,n) for(int i=0; i<(int)(n); i++)

int main(){
    int n; scanf("%d",&n);
    int a[101010];
    rep(i,n) scanf("%d",a+i);

    if(n==1){puts("1"); return 0;}
    int up=0,ans=1;
    rep(i,n-1){
        if(up==0){
            if(a[i]<a[i+1]) up=1;
            if(a[i]>a[i+1]) up=-1;
        }else{
            if((up==1&&a[i]>a[i+1])||(up==-1&&a[i]<a[i+1])){
                ans++;
                up=0;
            }
        }
    }
   
    printf("%d\n",ans);
}