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2020-10-21, 02:39   #23
0scar

Jan 2020

2×11 Posts

Quote:
 Originally Posted by SmartMersenne I really doubt that it will come anywhere close to July20.
I wish I could call you "pessimistic".
Looking at the past three years, Oct20 seems somehow similar to Nov17, another "find-constrained-algorithm" challenge. Nov17 was actually solved by 23 people only.
On the other hand, both Oct20 and July20 deal with linear-recurrenced sequences, candidate solutions can be analyzed with similar linear algebra methods.

About CHAOS, I found it useful to know that the following kind of instruction is permitted:
30 CHAOS 30, 40, 50, ...
so that the control flow graph has an edge from a one-line block to itself.

Last fiddled with by 0scar on 2020-10-21 at 02:47 Reason: Typos

2020-10-21, 06:47   #24
Dieter

Oct 2017

6116 Posts

Quote:
 Originally Posted by 0scar I wish I could call you "pessimistic". Looking at the past three years, Oct20 seems somehow similar to Nov17, another "find-constrained-algorithm" challenge. Nov17 was actually solved by 23 people only. On the other hand, both Oct20 and July20 deal with linear-recurrenced sequences, candidate solutions can be analyzed with similar linear algebra methods. About CHAOS, I found it useful to know that the following kind of instruction is permitted: 30 CHAOS 30, 40, 50, ... so that the control flow graph has an edge from a one-line block to itself.
But that isn't necessary! There are solutions for both problems (0,2,2,... and 1970) without using this trick.

2020-10-21, 11:10   #25
0scar

Jan 2020

2×11 Posts

Quote:
 Originally Posted by Dieter But that isn't necessary! There are solutions for both problems (0,2,2,... and 1970) without using this trick.
I agree at 100% with you.
Had it been necessary, writing it would have been too spoiling.
I only wrote that I found it useful (shorter code, faster reaching 1970)

2020-10-21, 12:42   #26
Dieter

Oct 2017

97 Posts

Quote:
 Originally Posted by 0scar I agree at 100% with you. Had it been necessary, writing it would have been too spoiling. I only wrote that I found it useful (shorter code, faster reaching 1970)
How fast? My fastest is 1970 = 10th value of the sequence, but I search no more.

2020-10-23, 09:41   #27
0scar

Jan 2020

2·11 Posts

Quote:
 Originally Posted by Dieter How fast? My fastest is 1970 = 10th value of the sequence, but I search no more.
The "trick" itself is just one more degree of freedom in writing code.
Of course I can remove all "tricky" edges from my solutions; the easiest way requires to keep the same number of incoming/outcoming edges by adding suitable nodes as new sources/destinations, which means some more CHAOS lines.
As an example, the length of my 7-step bonus solution grows from 17 to 19, not a problem, but I judge the "tricky" version more efficient.
So far, I found no "untricky" solutions which fit both the 6-step and the 20-line constraints.

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