I know in challenge problems, answer is tested against few test cases and rejudged after contest. But how the rating system works? In some problems, during contest, some AC solution get 0.000 points, some 0.001 and some 1.000.
How is 0.000 accepted?
How is it converted to points out of 100 at the end?
Are 0.000 point solutions rejected at the end or they will get some points too?
If they secure few points, will they be considered solved or partially solved?
In ACM-ICPC, or in IOI, does challenge level problem come?