《Cracking the Coding Interview》——第6章：智力题——题目4

2014-03-20 01:02

题目：无力描述的一道智力题，真是货真价实的智力题，让我充分怀疑自己智力的智力题。有兴趣的还是看书去吧。

解法：能把题目看懂，你就完成80%了，用反证法吧。

代码：

 1 // 6.4 There is an island with a bunch of people living there.

 2 // The strange thing is, any blue-eyed tourists must leave immediately when they find out they're blue-eyed.

 3 // Everyone can see others' eye colors, but not their own.

 4 // They know there'll be at least one blue-eyed tourists. If no more, the game ends.

 5 // Answer:

 6 //    Suppose there're n people and c are blue-eyed.

 7 //    If n == 1, that one will soon find out nobody else is blue-eyed, he'll leave on the 1st day.

 8 //    If n == 2, those two will see one blue-eyed, they are not sure if c == 1 or c == 2.

 9 //    But on the second day, when they still see each other, they know c == 2. Otherwise the one would have left. They'll leave on the 2nd day.

10 //    With mathematical induction, it can be proven that all the c blue-eyed will leave on the cth day together.

11 //    The most difficult part for me, is that when they can't be sure, they will simply stay. I thought every day there must've been someone leaving.

12 int main()

13 {

14     return 0;

15 }