2020多校第八场Clockwise or Counterclockwise

思路

利用向量的叉乘判断方向

代码

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <queue>
#include <cmath>
#include <cstring>

#define ll long long
using namespace std;
const int maxn=1e5+5;
const int N=5e6+5;

const ll mod=998244353;


ll power(ll x,ll a)
{
    ll ans=1;
    while(a)
    {
        if(a&1)
        {
            ans=ans*x%mod;
        }
        x=x*x%mod;
        a>>=1;
    }
    return ans;
}

int main()
{
    std::ios::sync_with_stdio(false);cin.tie(0);

    int t;cin>>t;

    while(t--)
    {
        ll x1,y1,x2,y2,x3,y3;
        cin>>x1>>y1>>x2>>y2>>x3>>y3;
        ll ans = (x2-x1)*(y3-y1)-(y2-y1)*(x3-x1);
        if(ans<0)
            cout<<"Clockwise\n";
        else
            cout<<"Counterclockwise\n";
    }
    return 0;
}