20160401--折点计数

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
	int n;
	cin >> n;
	int num[n];
	for (int i = 0;i < n;i++)
		cin >> num[i];
	int count = 0;
	for (int i = 1;i < n-1;i++)
	{
		if ((num[i - 1] - num[i])*(num[i] - num[i + 1]) < 0)
			count++;
	}
	cout<<count;
}