2. The champion can also be decided by the top two players in two groups in round robin, or the top two players cross each other (the first player in Group A is against the second player in Group B, and the first player in Group B is against the second player in Group A). Actually, the arrangement depends on how long you plan to hold the basketball game. 3. The lottery is divided into four groups, 2+2+3+3= 10, which is relatively fair because it is decided by lottery. Then each group will have a single round of competition, and the first group will qualify for the semi-finals and finals, so that the team with the most competitions will not exceed 4 games. 4、