Cut The Plane
시간 제한2초메모리 제한256 MB
세 점이 한 직선 위에 있지 않은 n개의 점이 주어질 때, 주어진 점을 지나지 않으면서 모든 점을 서로 다른 영역으로 나누는 ceil(n/2)개의 직선을 출력한다.
문제
There are distinct points in the plane, any three of which are not colinear.
You are asked to use distinct lines passing through no given points to cut the plane into pieces such that no two points lie in the same piece.
입력
There are multiple test cases. The first line of the input contains an integer , indicating the number of test cases. For each test case:
The first line contains an integer () -- the number of points.
Each of the following lines contains two integers and () describing a point in the plane.
It is guaranteed that there always exists a solution for each test case and the sum of in all test cases does not exceed .
출력
For each test case, output lines describing a solution.
Each line of them contains four integers , , and indicating a line through and , where and the absolute value of the coordinates should not exceed .