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
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
#include <iostream>
#include<vector>

using namespace std;

int main()
{

    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int n;
    cin >> n;
    vector<int> tab(n, 0);
    vector<int> silka(n, 0);
    int dl1 = 0;
    int dl2 = 0;
    int pom = 0;
    cin >> tab[0];
    silka[0] = tab[0];
    for (int i = 1; i < n; i++) {
        cin>>tab[i];
        if (pom == 0) {
            if (tab[i] >= silka[i-1]) {
                dl1++;
                silka[i] = -1000000000; 
            }
            else silka[i] = tab[i];
            pom = 1;
        }
        else {
            if (tab[i] <= silka[i-1]) {
                dl1++;
                silka[i] = 1000000000;
            }
            else silka[i] = tab[i];
            pom = 0;
        }
       // cout << dl1<<"  ";
    }

    //cout << endl;
    pom = 0;
    for (int i = 1; i < n; i++) {
        if (pom == 0) {
            if (tab[i] <= tab[i - 1]) {
                dl2++;
                tab[i] = 1000000000;
            }
            pom = 1;
        }
        else {
            if (tab[i] >= tab[i - 1]) {
                dl2++;
                tab[i] = -1000000000;
            }
            pom = 0;
        }
       // cout << dl2 << " ";
    }
    cout << min(dl1,dl2);

}