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<iostream>
#include<vector>

using namespace std;

int main()
{
    int n;cin>>n;
    vector<int> A(n);
    for(int i=0;i<n;i++)
    {
        scanf("%d",&A[i]);
    }

    int res=0;
    for(int i=0;i<n;++i)
    {
        //sameを抜ける
        while(i+1<n && A[i]==A[i+1])++i;

        //単調非減少
        if(i+1<n && A[i]<A[i+1])
        {
            while(i+1<n && A[i]<=A[i+1])++i;
        }
        //単調非増加
        else if(i+1<n && A[i]>A[i+1])
        {
            while(i+1<n && A[i]>=A[i+1]) ++i;
        }
        ++res;
    }

    cout<<res<<"\n";

}