解题思路
折点就是较高点或较低点
统计折点数量
当a[i] > a[i - 1] && a[i] > a[i + 1]时,该点为较高点,答案+ 1
当a[i] < a[i - 1] && a[i] < a[i + 1]时,该点为较低点,答案+ 1
代码实现
#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>
#include <sstream>
#include <set>
using namespace std;
const int N = 1010;
int a[N];
int main()
{
int n;
cin >> n;
for (int i = 1; i <= n; i ++) cin >> a[i];
int res = 0;
for (int i = 2; i < n; i ++)
{
if (a[i] > a[i - 1] && a[i] > a[i + 1]) res ++; //较高点
if (a[i] < a[i - 1] && a[i] < a[i + 1]) res ++; //较低点
}
cout << res;
return 0;
}