Careercup - Microsoft面试题 - 5204967652589568

2014-05-11 23:57

题目链接

原题：

9 identical balls. one ball is heavy. find the heavy ball with only 2 measurements ........ dead easy.

题目：9个看起来一样的球，其中有一个偏重。给定一个不能给出具体重量，但可以比较轻重的天平，称2次找出那个重球。

解法：9个球三等分，称一次找出包含重球的那三个。3个球三等分，称一次找出重球。

代码：

1 // http://www.careercup.com/question?id=5204967652589568

2 Answer:

3     Split the 9 balls into three groups of 3 balls.

4     Choose two groups and weigh them on the balance:

5         If balanced, the heavy ball is in the other group.

6         If imbalanced, the heavy ball is in the heavier group.

7     Find the group with the heavy ball, pick two balls from the three and weigh them:

8         If balanced, the heavy ball is the other one.

9         If imbalanced, the heavy ball is the heavier one.