CF EDU 111 C - Manhattan Subarrays

C - Manhattan Subarrays

枚举

多观察数据，发现当子数组中元素个数 >= 5 时一定不满足条件，因此枚举子数组个数为 3， 4 即可

#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>
#include <cmath>
#include <map>
using namespace std;
typedef long long ll;

const int N = 2e5 + 10;
const int INF = 2e9;
int n;
int a[N];

bool check(int l, int r)
{
	for (int i = l; i <= r; i++)
		for (int j = i + 1; j <= r; j++)
			for (int k = j + 1; k <= r; k++)
			{
				if (a[i] <= a[j] && a[j] <= a[k])
					return false;
				if (a[i] >= a[j] && a[j] >= a[k])
					return false;
			}
	return true;
}
int main()
{
	ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	int T;
	cin >> T;
	while(T--)
	{
		cin >> n;
		for (int i = 1; i <= n; i++)
			cin >> a[i];
		int ans = 2 * n - 1;
		for (int l = 1; l + 2 <= n; l++)
			if (check(l, l + 2))
				ans++;
		for (int l = 1; l + 3 <= n; l++)
			if (check(l, l + 3))
				ans++;
		cout << ans << endl;		
	}
	return 0;
}