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: Wrong Answer)

#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <vector>
#include <utility>
#include <cstdio>
#include <iostream>
#include <iomanip>
#include<string>
#include <stack>
#include<queue>
#include<map>
#include <stdlib.h>
#include <bits/stdc++.h>
#include <set>
typedef long long ll;
using namespace std;

int main() {
	ll n, cnt = 0, ucnt = 0, dcnt = 0;
	bool f = -1;
	cin >> n;
	vector<ll> v(n);
	for (ll i = 0; i < n; i++) {
		cin >> v[i];
	}
	for (ll i = 0; i < n - 1; i++) {
		if (v[i] < v[i + 1])
			ucnt++;
		if (v[i] > v[i + 1])
			dcnt++;
	}
	ll w = 0;
	w = min(ucnt, dcnt) + 1;
	cnt = 0;
	ucnt = 0;
	dcnt = 0;
	for (ll i = 0; i < n - 1; i++) {
		if (f == true) {
			if (v[i] > v[i + 1]) {
				f = false;
				cnt++;
				dcnt++;
			}
		} else if (f == false) {
			if (v[i] < v[i + 1]) {
				f = true;
				cnt++;
				ucnt++;
			}
		} else {
			if (v[i] < v[i + 1]) {
				f = true;
			} else if (v[i] > v[i + 1]) {
				f = false;
			}
		}
	}

	ll w1 = 0;
	if (ucnt > dcnt) {
		w1 = ucnt + 1;
	} else if (dcnt > ucnt) {
		w1 = dcnt + 1;
	} else {
		w1 = cnt + 1;
	}
	ll w2 = min(w, w1);

	cout << w2 << endl;

	return 0;
}