Interview Questions: Find repeated numbers from the array of 1001 integer Elements

Original article, copyright belongs to Hu Tian Fa (hutianfa@163.com) All, reprint please indicate the source:
Http://blog.csdn.net/aidisheng/archive/2008/09/24/2972497.aspx

 

Question:

There is an array with a length of 1001 (Suppose it is A), which stores the one thousand integers from 1 to unordered, and an element is an integer from 1, use the best algorithm to find the repeated integer.

 

My answer (implemented in Ruby ):

1. #
2. # Program: Find repeated numbers from the array of 1001 integer Elements
3. # Author: Hu Tian Fa (hutianfa@163.com)
4. #
5. Def find_duplicate Array
6. H = {}
7. Array. Each do | I |
8. If H. Include? I. to_s.to_sym
9. Puts "find I:" + I. to_s
10. Return
11. Else
12. H. Merge! I. to_s.to_sym => I
13. End
14. End
15. End

Test:

1. A = [1, 2, 3, 4, 5, 4]
2. Find_duplicate

Output result:

1. Find I: 4