不多说了，代码奉上

#include <iostream>
#include <vector>

using namespace std;

int main() {
    int N;
    cin >> N;
    vector<int> phi(N + 1);
    for (int i = 0; i <= N; i++) {
        cin >> phi[i];
    }
    int cnt = 0;
    for (int i = 0; i < N; i++) {
        if (phi[i] * phi[i + 1] < 0) {
            cnt++;
        }
    }
    cout << cnt << endl;
    return 0;
}

帮我看看，谢谢！！！！