The steps are as follows:

The number 12 is 1- 12.

For the first time, put 1-4 on the left and 5-8 on the right.

If the first weight, the bad ball in 1-8.

Remove the number 2-4 for the second time, move the number 6-8 from the right to the left, and put the number 9- 1 1 on the right. That is to say, put 1, 6, 7, 8 on the left and 5, 9, 10,1/on the right.

If the second weight, the bad ball in the untouched number 1, 5. If it is 1, it is lighter than the standard ball; If it's a No.5 ball, it's heavier than the standard ball.

Put 1 on the left and No.2 on the right for the third time. If the right ball is heavy, 1 is a bad ball, lighter than the standard ball; If it is balanced, the No.5 ball is a bad ball, which is heavier than the standard ball; It's impossible to be dumped this time.

If the ball is balanced for the second time, the number of bad balls removed is 2-4, which is lighter than the standard ball.

Put No.2 on the left and No.3 on the right for the third time. If the right ball is heavy, the No.2 ball is a bad ball and lighter than the standard ball; If it is balanced, the No.4 ball is a bad ball, which is lighter than the standard ball; If the left side is heavy, the No.3 ball is a bad ball and lighter than the standard ball.

If the left ball is heavy for the second time, the bad ball will get the left 6-8, which is heavier than the standard ball.

For the third time, put No.6 on the left and No.7 on the right. If the right ball is heavy, the No.7 ball is a bad ball, which is heavier than the standard ball; If it is balanced, the 8 th ball is a bad ball, which is heavier than the standard ball; If the left ball is heavy, then the No.6 ball is a bad ball, which is heavier than the standard ball.

If the left is heavy for the first time, the bad ball is also in 1-8.

Remove the number 2-4 for the second time, move the number 6-8 from the right to the left, and put the number 9- 1 1 on the right. That is to say, put 1, 6, 7, 8 on the left and 5, 9, 10,1/on the right.

If the second right is heavy, the bad ball will get 6-8 left, which is lighter than the standard ball.

For the third time, put No.6 on the left and No.7 on the right. If the right ball is heavy, then the 6 th ball is a bad ball, which is lighter than the standard ball; If it is a balance ball, the 8 th ball is a bad ball, which is lighter than the standard ball; If the left ball is heavy, the No.7 ball is a bad ball, which is lighter than the standard ball.

If the ball is balanced for the second time, the bad ball is heavier than the standard ball in the removed number 2-4.

Put No.2 on the left and No.3 on the right for the third time. If the right ball is heavy, the No.3 ball is a bad ball, which is heavier than the standard ball; If it is balanced, the No.4 ball is a bad ball, which is heavier than the standard ball; If the left ball is heavy, the No.2 ball is a bad ball, which is heavier than the standard ball.

If the second left is heavy, the bad ball is in the untouched numbers 1 and 5. If it is 1, it is heavier than the standard ball; If it's a No.5 ball, it's lighter than the standard ball.

Put 1 on the left and No.2 on the right for the third time. If the left ball is heavy, the No.5 ball is a bad ball and lighter than the standard ball; If it is balanced, the number 1 is a bad ball, which is heavier than the standard ball; It can't be right-handed this time.

If it is the first balance, the bad ball is 9- 12.

The second time, put 1-3 on the left and 9- 1 1 on the right.

If the second right is heavy, the bad ball is 9- 1 1, which is heavier than the standard ball.

Put No.9 on the left and 10 on the right for the third time. If the right ball is heavy, 10 ball is a bad ball, which is heavier than the standard ball; If it is a balance ball, 1 1 ball is a bad ball, which is heavier than the standard ball; If the left ball is heavy, the No.9 ball is a bad ball, which is heavier than the standard ball.

If the second balance, the bad ball is 12.

For the third time, put 1 on the left and 12 on the right. If the right ball is heavy, then 12 is a bad ball, which is heavier than the standard ball; If the left side is heavy, then 12 is a bad ball, lighter than the standard ball; It is impossible to balance at this time.

If the second left is heavy, the bad ball is 9- 1 1, which is lighter than the standard ball.

Put No.9 on the left and 10 on the right for the third time. If the right ball is heavy, then the 9 th ball is a bad ball, which is lighter than the standard ball; If it is a balance ball, the number 1 1 is a bad ball, which is lighter than the standard ball; If the left ball is heavy, 10 is a bad ball and lighter than the standard ball.

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