两个网站都通过

#include <iostream>
using namespace std;
const int N = 1010;

int n;
int a[N];

int main()
{
    cin >> n;
    for(int i = 0; i < n; ++ i) cin >> a[i];

    int cnt = 0;
    for(int i = 1; i + 1 < n; ++ i)
        if((a[i - 1] - a[i]) * (a[i + 1] - a[i]) > 0) cnt ++;

    cout << cnt << endl;

    return 0;
}