將list集合，元素隨機打亂

 

• for循環+隨機數 實現相同位置的元素交換

• public <T> void shuffle(List<T> list) {
          int size = list.size();
          Random random = new Random();
  
          for(int i = 0; i < size; i++) {
  
              int randomPos = random.nextInt(size);
  
              T temp = list.get(i);
              list.set(i, list.get(randomPos));
              list.set(randomPos, temp);
          }
      }

• Collections.swap實現

• public <T> void shuffle(List<T> list) {
          int size = list.size();
          Random random = new Random();
  
          for(int i = 0; i < size; i++) {
  
              int randomPos = random.nextInt(size);
  
              Collections.swap(list, i, randomPos);
          }
      }

  Collections.shuffle實現

• public <T> void shuffle(List<T> list)
   { 
  Collections.shuffle(list); 
  }