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 <stdio.h>
#include <cstdlib>

void scanData(int *array, int size) {
    for (int i = 0; i < size; ++i) {
        char buffer[100001];
        char *remain;
        scanf("%s", &buffer[0]);
        array[i] = (int)atol(buffer);
    }
}

void print_array(int *array, int size) {
    if (size == 0) return;
    printf("%d ", array[0]);
    print_array(array + 1, size - 1);
}

int count(const int *array, int size) {
    enum Arranged {
        None = -1,
        Ascending,
        Descending
    };

    int splitNum = 0;
    Arranged arranged = array[0] < array[1] ? Ascending : Descending;
    Arranged prevState = arranged;
    for (int i = 1; i < size - 1; ++i) {
        if ((arranged == Ascending && array[i] > array[i + 1]) || (arranged == Descending && array[i] < array[i + 1])) {
            splitNum++;
            i++;
            arranged = array[i] < array[i + 1] ? Ascending : Descending;
        }
    }

    return splitNum + 1;
}

int main() {
    int *array;
    int array_len;

    scanf("%d", &array_len);
    if (array_len == 1) {
        printf("0");
        return 0;
    }
    array = (int*)malloc(sizeof(int) * (size_t)array_len);

    scanData(array, array_len);
    printf("%d", count(array, array_len));

    free(array);

    return 0;
}