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 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<stdlib.h>

int calc(int *a,int n){
  int i=0;
  int ans=0;
  while(i<n){
    ans++;
    int j=i+1;
    while(j<n && a[j]==a[i]) j++;
    if(j>=n) break;
    int sign=a[j]-a[j-1]>0?1:-1;;
    while(j<n && sign*(a[j]-a[j-1])>0) j++;
    i=j;
  }
  return ans;
}

void run(void){
  int n;
  scanf("%d",&n);
  int *a=(int *)calloc(n,sizeof(int));
  int i;
  for(i=0;i<n;i++) scanf("%d",a+i);
  int x=calc(a,n);
  printf("%d\n",x);
}

int main(void){
  run();
  return 0;
}