【思维】【CF1550】 C. Manhattan Subarrays

CF1550 C. Manhattan Subarrays

传送门

思路及分析：

补题代码

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
bool judge3(int a,int b,int c)
{
	return !( (a<=b&&b<=c) || (a>=b&&b>=c) );
}
bool judge4(int a,int b,int c,int d)
{
	return (a>b&&c>a&&d>b&&d<c) || (a<b&&c<a&&d<b&&d>c);
}
int main()
{
	int t;
	cin>>t;
	while(t--)
	{
		int m;
		cin>>m;
		int a[m+1];
		for(int i=0;i<m;i++)
		    cin>>a[i];
		if(m==1)
		    cout<<1<<endl;	
		else if(m==2)
		    cout<<3<<endl;
		else if(m==3)
		{
			if(judge3(a[0],a[1],a[2]))
			    cout<<6<<endl;
			else cout<<5<<endl;
		}
		else
		{
			ll ans=m+m-1+judge3(a[m-3],a[m-2],a[m-1]);//提前处理一和二还有三中的一种情况 
			for(int i=0;i<m-3;i++)
			   ans+=judge4(a[i],a[i+1],a[i+2],a[i+3])+judge3(a[i],a[i+1],a[i+2]);
	        cout<<ans<<endl;
		}
	}
	return 0;
}