# RogerBW's Blog

 The Weekly Challenge 210: Collisions Kill 02 April 2023 I’ve been doing the Weekly Challenges. The latest involved searching in lists of integers. (Note that this closes today.) Task 1: Kill and Win You are given a list of integers. Write a script to get the maximum points. You are allowed to take out (kill) any integer and remove from the list. However if you do that then all integers exactly one-less or one-more would also be removed. Find out the total of integers removed. This is simpler than it looks, because the rules ensure that all numbers will eventually be removed, either by direct choice or by being adjacent to a direct choice - and both ways count towards the score. Therefore, whatever order this happens in, the actual answer is simply the sum of all the list values. Raku: ``````sub killandwin(@a) { return @a.sum; } `````` Task 2: Number Collision You are given an array of integers which can move in right direction if it is positive and left direction when negative. If two numbers collide then the smaller one will explode. And if both are same then they both explode. We take the absolute value in consideration when comparing. All numbers move at the same speed, therefore any 2 numbers moving in the same direction will never collide. Write a script to find out who survives the collision. I don't think there are any timing considerations - if elements 2 and/or 3 eliminate each other, their neighbours needn't be reconsidered until the next pass. Standard clean/dirty flag loop. Ruby: ``````def numbercollision(aa) a = aa dirty = true while dirty do b = [] dirty = false i = 0 while i + 1 <= a.length do `````` If there's a collision at all: `````` if i + 1 < a.length && a[i] > 0 && a[i + 1] < 0 then ab = a[i + 1].abs `````` Larger first number is retained `````` if a[i] > ab then b.push(a[i]) `````` Or larger second number is retained `````` elsif a[i] < ab then b.push(a[i + 1]) end `````` Or nothing is, if they were equal. `````` i += 2 dirty = true `````` Or there wasn't a collision and we just copy. `````` else b.push(a[i]) i += 1 end end a = b; end return a end `````` Full code on github. Comments on this post are now closed. If you have particular grounds for adding a late comment, comment on a more recent post quoting the URL of this one. Search 10 per page 20 per page 50 per page 100 per page Archive Tags 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s 3d printing action advent of code aeronautics aikakirja anecdote animation anime army astronomy audio audio tech aviation base commerce battletech beer boardgaming book of the week bookmonth chain of command children chris chronicle church of no redeeming virtues cold war comedy computing contemporary cornish smuggler cosmic encounter coup covid-19 crime crystal cthulhu eternal cycling dead of winter doctor who documentary drama driving drone ecchi economics en garde espionage essen 2015 essen 2016 essen 2017 essen 2018 essen 2019 essen 2022 essen 2023 existential risk falklands war fandom fanfic fantasy feminism film firefly first world war flash point flight simulation food garmin drive gazebo genesys geocaching geodata gin gkp gurps gurps 101 gus harpoon historical history horror hugo 2014 hugo 2015 hugo 2016 hugo 2017 hugo 2018 hugo 2019 hugo 2020 hugo 2021 hugo 2022 hugo 2023 hugo 2024 hugo-nebula reread in brief avoid instrumented life javascript julian simpson julie enfield kickstarter kotlin learn to play leaving earth linux liquor lovecraftiana lua mecha men with beards mpd museum music mystery naval noir non-fiction one for the brow opera parody paul temple perl perl weekly challenge photography podcast politics postscript powers prediction privacy project woolsack pyracantha python quantum rail raku ranting raspberry pi reading reading boardgames social real life restaurant reviews romance rpg a day rpgs ruby rust scala science fiction scythe second world war security shipwreck simutrans smartphone south atlantic war squaddies stationery steampunk stuarts suburbia superheroes suspense television the resistance the weekly challenge thirsty meeples thriller tin soldier torg toys trailers travel type 26 type 31 type 45 vietnam war war wargaming weather wives and sweethearts writing about writing x-wing young adult Special All book reviews, All film reviews
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