If the teacher guessed that Daming didn't win the gold medal, it was wrong to guess that Sisi won the gold medal, then Qiu Qiu won the gold medal, and the teacher said that Qiu Qiu didn't win the gold medal was right and contradictory!
If the teacher guessed correctly that Qiu Qiu didn't get the bronze, it would be wrong for Daming not to get the gold, so Daming got the gold and the silver that autumn.
In a word, Daming has gold and Qiu Qiu has silver and copper.