2019牛客多校(第一场)F-Random Point in Triangle
#include <bits/stdc++.h> using namespace std; typedef long long ll; struct Point{ ll x, y; Point( ll x=0, ll y=0 ): x(x), y(y){} }; typedef Point Vector; Point p[5]; Vector operator -(const Vector a, const Vector b ){ return Vector( a.x-b.x, a.y-b.y ); } ll Cross( Vector a, Vector b ){ return a.x*b.y - a.y*b.x; } int main(){ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); ll x1, y1, x2, y2, x3, y3; while( cin >> x1 >> y1 ){ cin >> x2 >> y2 >> x3 >> y3; p[1] = Point(x1, y1); p[2] = Point(x2, y2); p[3] = Point(x3, y3); ll ans = Cross( p[2]-p[1], p[3]-p[1] )*11; if( ans<0 ) ans = -ans; cout << ans <<endl; } return 0; }