Upstairs, that's the positive solution. That's what I thought. I started with 1, which means that No.3 is the first, that is, No.3 1. From another athlete who won the third place, he said, "1 is not the fourth place." We can know that 1 is the second place, because the third place says that 1 is not the fourth place, which only means that 1 is the second place. The rest is that No.2 and No.4 don't know the ranking, and No.2 and No.4 may rank 34 or 43. According to the teacher, No.4 is definitely not the fourth place. So No.4 is the third and No.2 is the fourth, so it can be seen that:

Third place, first place

12

Fourth place, third place

Second place, fourth place