I don't think it's the interpreter's strategy that is at fault. odo
3#1e6 is asking the machine to create a set of 1e18 triplets, which you
will then presumably check to see if they add to 1e6, and then cast out
duplicates. If somehow the interpreter could feed you the 1e18 values
one at a time, you still wouldn't get to a solution.
A better strategy is to read about partitions and generating functions
thereof.
Henry Rich
On 5/19/2018 5:58 PM, james faure wrote:
This is a good example of a very annoying limitation of the current
interpreter's eager evaluation strategy, in this case one is forced to come up
with some sort of non-idiomatic iterative 'hack' to get a result. Concretely, I
guess you're forced to use an accumulator with ^: or an explicit loop, which
hurts.
________________________________
From: Programming <programming-boun...@forums.jsoftware.com> on behalf of Skip Cave
<s...@caveconsulting.com>
Sent: Saturday, May 19, 2018 10:43 PM
To: programm...@jsoftware.com
Subject: [Jprogramming] Quora Problem
Another interesting quora problem:
How many distinct triplets have a sum of 1,000,000 (provided all numbers
are integers and are positive)?
<https://www.quora.com/qemail/track_click?al_imp=eyJ0eXBlIjogMzUsICJoYXNoIjogMTcxMDQ0NjU4Mn0%3D&al_pri=QuestionLinkClickthrough&aoid=oMo937UDzj8&aoty=2&aty=4&click_pos=1&ct=1526747413834671&et=103&id=62216bf7b30d40aea1d79bf4401c8317&request_id=289&src=1&st=1526747413838426&stories=2518686273&uid=bqluVqSeN78&v=0>
The obvious straightforward solution would be to use the odometer verb:
odo=: #: i.@(*/)
1e6=+/"1 odo 3#1e6
|limit error: odo
| 1000000=+/"1 odo 3#1000000
Ooops. Unfortunately, I don't have near enough memory to use this approach.
Any suggestions?
Skip
Skip Cave
Cave Consulting LLC
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