1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
#include <iostream>

using namespace std;

int main(){
    int n, cnt_a = 0, cnt_b = 0; // a - pierwszy rosnacy, b - pierwszy malejacy
    cin >> n;
    bool a_changed = false, b_changed = false;
    int v1, v2;
    cin >> v1;
    for(int i = 1; i < n; i++){
        cin >> v2;
        if(i % 2 == 0){
            if(v2 - v1 >= 0 && !a_changed){
                a_changed = true;
                cnt_a++;
            } else
                a_changed = false;
            if(v2 - v1 <= 0 && !b_changed){
                b_changed = true;
                cnt_b++;
            } else
                b_changed = false;
        } else{
            if(v2 - v1 >= 0 && !b_changed){
                b_changed = true;
                cnt_b++;
            } else
                b_changed = false;
            if(v2 - v1 <= 0 && !a_changed){
                a_changed = true;
                cnt_a++;
            } else
                a_changed = false;
        }

        v1 = v2;
    }
    cout << min(cnt_a, cnt_b) << endl;
}