Thank you all
, Your algorithms are all faster than me.
In my PC, (E7500 CPU, 4G Mem)
Ronjonp 's code, about 34.812967s
Lee Mac's code, about 40.733018s
Gile's code 42.111982s
alanjt's code is about 50s
Mine first code is very slow.
, (could you tell me which cause the very slow)
Not very accurate test.
And I hope to see pkohut's super code
I am thinking about the "Divide and conquer algorithm", but I need some time to sort the point in some manner, and not so sure about whether it can be improved, because the sort also need some times.