链接:http://118.190.20.162/view.page?gpid=T42

代码：

#include<bits/stdc++.h>

using namespace std;

vector<int> ve;

int main (){
    int n,num;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>num;
        ve.push_back(num);
    }
    int ans=0;
    for(int i=1;i<n-1;i++){
        if(ve[i]>ve[i-1]&&ve[i]>ve[i+1])ans++;
        if(ve[i]<ve[i-1]&&ve[i]<ve[i+1])ans++;
        
    }
    cout<<ans;
    return 0;
}