It seems to me that:
checkio([[0, 0], [1, 1], [1, 1], [3, 3]])==True
checkio([[0, 0], [1, 1], [2, 2], [3, 3]])==False
checkio([[0, 0], [1, 1], [3, 3], [2, 2]])==True
but many accepted solutions do not give these answers.
Created at: 2012/11/16 08:36; Updated at: 2013/09/30 13:46