MRECAMAN - Recaman’s Sequence
English | Vietnamese |
The Recaman’s sequence is defined by a0 = 0 ; for m > 0, a(m) = a(m−1) − m if the resulting a(m) is positive and not already in the sequence, otherwise a(m) = a(m−1) + m. The first few numbers in the Recaman’s Sequence is 0, 1, 3, 6, 2, 7, 13, 20, 12, 21, 11, 22, 10, 23, 9 · · · .
Given k, your task is to calculate a(k).
Input
The input consists of several test cases. Each line of the input contains an integer k where 0 ≤ k ≤ 500000. The last line contains an integer −1, which should not be processed.
Sample Input 7 10000 -1
Output
For each k given in the input, print one line containing a(k) to the output.
Sample output 20 18658
Added by: | psetter |
Date: | 2009-02-23 |
Time limit: | 1s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ERL JS-RHINO NODEJS PERL6 VB.NET |
Resource: | Pre Shanghai 2004 |