⌨️

Run-Length Encoding

Week 34

You are creating some monitoring software - it can be used for your websites, IoT devices, sensors etc. Some of these devices have low memory, but their status is checked at millisecond intervals - you want to log their all statuses, but don't have enough space on them to store data for each interval separately

Instead, you remember back to your school textbooks which mentioned that run-length encoding (RLE) works well for simple, usually digitally-created images that have long consecutive patterns of identical pixel values. Classic game images with a low colour palette are great examples of such images. Likewise, you realise that your websites, sensors etc will likely have large periods of consecutive statuses - i.e. TTTTTTTTTTTTTTTTTTTFFFFFFFFFFFTTTTTTTTTTT (e.g. the above scenario represents T = initially working, then F where something went wrong, then T again when someone fixed it). It is very unlikely statuses will toggle frequently like TFTFTFTF etc - run-length encoding will hence work very well in this situation

The RLE values to be calculated is simply the count for the current character, then the character itself - below you can see some example strings and how they should be encoded according to RLE:

aaaaabbb 5a3b i.e. 5 a's, then 3 b's abcde 1a1b1c1d1e [in the example above, we can see when having frequently changing characters RLE is not memory efficient and will actually use MORE storage, since we have to store the count, along with the data] hhhheeelllllllooowwwwwwwoorrrrrrllllllddddddd 4h3e7l3o7w2o6r6l7d TTTTTTTTTTTTTTTTTTTFFFFFFFFFFFTTTTTTTTTTT 19T11F11T !!! $$$$ ****..@@@@@@ 3!5 4$1 4*2.6@

Your program should only output the RLE version (e.g. like the "19T11F11T" above) and NOT the original string for the following string (note: this is a single line string - it gets wrapped in the textarea, but just copy it wholly - don't include any line breaks):

Ruuunnnnn---llllllleeeeeenngggggggggtttthhhhhhh ennnnnnnncccccccoooooddddddddinnnnnnnnnggggggggg ((((((RRLLLLLE) iiissssssss aaaaaaaaa ffffffffoooooooorrrrrrrmm oooooooof lloooooosssslllllleeeeeeeesssssss ddaaaaaaattttttttttaaaaaaaa ccccccccoommmmmmmmpprrrreeeeeeeesssssssssiiiioooooooonnnn iiinnnnnn wwwwwhhiccccccccchhhhh rrrrrruunnnnnnnnnnsssssssss of dddddaaattttttttaaaaaaaaaa (((((((ccooooooonnnnnnnnnnsssssseccccccuuuuuuuuttttttiivvvvvvee oooccccccccccccccuuuuuuuuurrrrrrrrrrreeeeeeennncccccccccceeeeeeeessssss ooooffffffff ttttttheeeee ssssssssssaammmmeeeeee ddddddddddaaaaaaaattttttttttaaaaa vvvvaaaaaaaallluuuuuuuueeee)))))) aaaaaaaaaarreeee ssttooooooooorrrrrrreddd aaasss aaaaaaa sinngleeeeee ooooooccccurrrrrrrrrrrennnccccceeeeeee ooooooofff tttthhhhhaaaaaaaattt dddddaaaaaaaataaaa vvvvvvvvvaaaalllllluueee aaaannnndddddddd aaaaaaaa cccccccccouuuuuuuuuunnnnnnnnntttttttt oooooofffffffff iiiittttttsssssssss ccccccccccoooooonnnnsssssseeeeeeeeecccccuuuuuutttttttivvvvvvvvvveeeeeeee ooooooooocccccccccuuuuuuurrrrrrrrrreeennnnnnnncccccccceesss,,,,,,, rrrraaaathhhhhhheeeeeeeeeerrrrrrr ttttttthhhaan aaaaaaaaass theee orrrrrrrrrrigggginnnnnnnnnaaallllll ruunnnnnnnnn... FFFFFFFoooooorr eeeeeexxxxaaaammmmmmmmmpppllllllllleee,,,,,,, aaaaa ssssseeeeeeeeeqqqqqqqquuuueeeeeeennnnncccccccccee ooff """"""""ggrrreeeeeeeeeeeeeeennn gggrrrrrrrrreeeeeeeeeeeeeeeeeennnnnnn gggggggrrrrreeeeeeeeeennn gggrrrrrrrrrreeeeeeeennnnnnn grreeeeeeeeeeeenn""""" iiiiiiiiiinnnnnnnnnn aann iiiiimmmagggggggggee bbbuuuuuuuiiiiiiiltttttttt uuuppp frromm ccccoooolllllllllooooooooreeeeeedddddd ddddooooooottttttttsssss coooooouullllddd bbbbbbeeee sssssssssshhhooooorrrrtttttttteeeennnnneeeeeeeddddddd tttttttttooooooooo """"""""gggggrrrrrrrreeeeeeeeeeeeeeeeennnnnnnnnn xxxxxxxx 5555555555"""""""... RRuuuuuunnnnnnn--lllleeeeeeeeeennggggggggggtttttttthhhhh eeennnnccooddddddddddinnnnnnnnggggg iiiiiiiiisssssssss moooooooooosssstttt eeeeeeeeefffffffffffffffffiiiiccciiiiiienttt oooooooooon dddddddattttttaa tthhhhhhhhhhaaaaaaatttttttt ccccooooooooonnnnnnnnnttttttttttaaaiiiiiiiiiinnsssss mannnnyyyyy sssssuuuuccccccchhhhh rruuunnnnss,,, fffoooooooorrrrrrrrrr eexxxxaaaaammpppppppppleeeeeee,,,,, sssssssiiimmmmmmmppllleeeeeeeee gggggggrrrrraaaaapphhhhhhiiiiic iiiiimmmmmaggeeeeeeeessssssss ssssssssssuuuuuuucccchhh aaaaaasssssssss iiiiiicooooonssssss,,,,,, lllllllliiiiiineeeeee dddddddrrrraawwwiiiiiiiiiinnnnnggggggggssssss, gggggggggaaaaaaammmeeeeeeeeees, aaaaaandddddd aaaaaaannniimmmmmaaaatiionnnnnnnnnnssssssss.......... FFFFoooooooorrrr fffffffiiles ttttttthhatttttt dddoo nnoooootttttt hhhhaaavvvvvvvvveeeeeeeeee mmmmmmmannyy rrrruuuuuuuunnnnnnnnss,,,,, eeennnnccccccccooooooooooddddddddddiiiiiiiiing tttttttthheeemmm wwwwwwwwwwithh RLLLLLEEEEEEEEE ccccccooooouuuuuuuuuullllld iiiiiiinncccccccrrrrrrreeeeaaaaaaaasssssssssseeee ttttttttthhhhhhhhhee ffffffffffiiiiiiiiiilleeeeeeeeee sssssssiizzzzeeeeeeeee....... RRRRLLLLLLLLEEEEEEEE mmmmmmmmmmaaaaaaaayyyyyyyyy aaaaaaallllllllllsoooooooo rrreeeeeeefffffeeeeeeeeerr tttooooo ppppaaarrrrrrrttttttttttiiiiiicccccuuuuuuuuullllllllaaaaaaaarrrrrrrrr iiiiiiiimmmmmaaggggee ffoooooooorrrmaaaaaaaaaattttttsss thhhhhhhhhaaaattttttt uuuuuuuusssssseeeeeeeeee ttttttthhhhhheeeeeee eeeeeeeennnncccccccoddddddddddiiinnnnnngggggggg......... RLLLLLEEEEEEEEE isssss aaaaaaaaaannnn eeeeeearrrrrllllllllyyyyy ggrraaaaaaappphhiiiiiiccccs fffffffffiiiiilleeeeeee ffffffoooooorrrrmmmmmmaaaaaaaatttttttttt ssupppppppppppporrrrrtteeeeddd bbbyyyyyyy CCCCCCCCCoommppppppppuSSSSSSSSeerrrrrrrrrveeee fffffoooooooorrrrr cccoooooooommmmmmmmmmppppppprrrrrrrrrreeeeesssssssssssiiiiinnngggggggggg bbbbbbbbbbllaaaaaccccckkkkkkkkkk aaaaaaaannnnnnndddddddddd wwwwwwhhhhhhhhiiiiittttttttteee iiiiiiiimmmmmaaaaaggeeeeeesss, ttttthhhhhaaaatttttttt wwwwaaaaaaassssss wwwiiiiideeeeeeeellllllllyy sssssuuuuuuuuuupppppppppppllllllllaaaantttttttttteeeeeeeeddd bbbbbbby ttttttthhhhhheeeeeiiiiiirrrrrr laaatttttttttteeeerrr GGGGGGGGGGrrrrrraapppppphhhhhhhhiiiiiicss Innnntttttttttteeeeeerrrrrrrrrrcccchhhhhhaaaannngggeeeeee FFFFFoooooooooorrmmmmaaaaaaattttt (((GGGGIIIFFFFFF))))))....... IIIt iiiiiiiiisssssssss aaaallssssssssoooo thhhhhhhhhhe nammmmmmmmmmeeeee oooooooffffff aaaaaaaa llllliiiiiiittttttlllllllllleeeee-----ussseedddddd iiiiiiiiiimmmmmmmmmaaaaaaagggggggggge fffffffoooooorrrrrrrrrrmmmmaaaaaattttttt iinnnnn Wiinnnnnnnnddddddddoooooooowwwsssssss 333333.......xxxxxxxxxx tttttttthaaaaaaaaatttttt iiiiiiiiissss sssssssssavvvvvvvveeeeeeedddddd wwwwwwwwwiiiiittttttthh ttttthhhhhheeeeee ffffffffffiiiiiiiiiillllllllle eeeeeeeexxxxxxttennnnnnnnssiiionnnnnnnnn rrrrrrrrllllllllleeeeeee,,, cccccccccooooooonnnnssiissssssttttttttiiiiiinnnnnngggggggggg oofffffffff a rrruuuunnnnnnn----llllleeeeeeeennnnnnnnngggggggggtttttttthhhhhhhhh eeeeeeeenccccccccoooodddddeddddddddd bbbbbbbbiiiiittttttttttmmmmmmmmmmaaaaaaaappppppp;;;;;;;; iiiit wwwwasss usseeeeddddddddd aassssss ttttthhhhhhhheee ffffoorrrrrmmmmmmmmmaaaaaaaattttt ffffffffoooooooorrrr tttthhhhheeeeeeee WWWiiinnnddddddowwwwwwssssss 33......xxxxxxxxxx sssssssssttttttaaaaarrrtttttttttuuppppp sssssssssscccccccccrrreeeeeeeeeeeeeeeeeeennnnnnnnnn... HHHiiiiiiissssssttttttorrryyyyyyyyyy aaaannnnnnnnnddddddd aaaaaaappppplllllllliiiiiiccatiiiiiiiiiooooooonnnnssssss. RRRRuuuunnnnnnn---------lllllllllleeeeeeeennnnnnnnnnggggggggggtttttttttthhhh eeeeeeeeennncccccccccoooddddddddddiiiiiinnnnngg (((RLLLLLLEE))))) ssssscchhhheeeemeeeeeeeeess wwwerrreeeeeeeeee eeemmmpppppppllooooooooooyyyeeeeedddd iiiiiiiiiinn ttttttttthhhhhhhhhheeeeeeee tttrrrrrraaaaaaaannnnnnnnnsmiiiiiiissssssssssssssssssssiooooooooonnnnnnn offff aaaaaaaaannnnnaaaaaaaallllllllloooogg ttttttttteellllleeeeevvvvviiiiiiissssiionnnnnnn ssssssssssigggggggggnnnnaallllls aassssss ffffaaaaaaaar bbbbbaaaccccckkkkkkk aass 11111111999666666666677......... IIIIIIIInn 1198888888833333,,,,,,,, rruuuuunnnnn------llllleennnnnnngtttttttttthh eeeeennnnnnccccccoooooooodddddddddiiiiiinnnnnnnngg wwwwwwaaass pppppppppaaaaaaatteeeeeeeeennnnnnttttteeeeeedddddddddd bbbbbbbbbyyyyyy HHHHHHHHHiiiiiiiitttttaaaaaacccccchhhhhhiiiiiiiii... RRLLLLLLEEEEEEE iiiiiisssss ppaaaaaaaarrrrrrrrrrtttttttttiiicccccccularrlllllllyyyyyyyy wwwweellllllllllll sssssssssuuuuuuuiiiiiittttteeddddddddd ttooo pppaalllllllllleeeeeeeetttttttttttttttteeeeeee----------bbbbbbbbaaseeeeeeedddddddd bbiiiiiiiiiittttttttttmmmmmmmmapppppppp immmmmmmaaagggggggeesssss ((((wwwwwwwwwwhhhhhhhiiiiiiiiicccccccchhhhh uuuuuuuuusssssssssseeee rrreeeeeeeelllllllllaaaaaaaaatttttttttiiiiiiiiiivvvvvvvvveeeeeeeelyyyyyyyy fffeewwwww cccccccccoooollllllooooooooorrrrrssssssss)))))) succccccch aaaasss ccccccooooooooommmmmmmmputttttttttteeeeeeeerrrrrrr iiiiiiiicooooooonnsss,,,,,,, aaaaaanddddd wwwwwwwwwaaaaaaaassssss aaaaaaaa ppppppppooooooooooppppppuuuuuuuuuulllllllllaaaaaaaaaarrrr iiimmmmaggggggeeeeeeeeee cccccccoooooommmppppprrrreeeesssssiioooooooooonnnnnnnnn mmmmmeeeeetttttttthhhhhhhooooooooood ooon eeaaarlllllllllyy oooooooonnnnnnllinnnnnnnnneeeeeee ssseeeeeerrrrrrvvvvvvviiiiiiicceeeeessssssss sssuuucccchh aaaaaaaaaasss CCCCCCCCCCoooooommmppppuuuuuuuSeeeeeeeerrrrrrrrrrvvvvvee bbbbbbbbeeeeeeeeffffooore tttttthhhhhheeeeee aaaadddvvvvveennnttttt oooofffff mmmmmmooooooooorrrrreeee sooooppppppphhhhhiiiiiiisssssssttttttttticccccccccaateeeeeeeeddd fffoorrrrrrrrrmmmmmmmmmmaaaaaaaattttss ssssssssuuuuuuuucccccccchhhhhhhhhh aaaasssssss GGGGGGGIIIFFFFFFFFF....... IIIItt dddddddoooooooeesssss nnnnnnnnnnoooooooooottt wwwwoooooorrrrrk wwwwwwweeeeeelllllllllllllll ooooooooonnn ccccccccccooooooonnttinnnnuuuuuooooooouuuuuuussssssss-------ttttttttooooooooonnnnnnnnnneeeeee iiiiiiiimaaaaaaaaageeeeeees (wwwwwhhhhhhhhicccccccchhhhhhhhh uuuusseeeeeeee vvvvvvveeeeeeeerrrrrrrrrryyyy mmmaaaaaannnyyyyy ccooooooolllllllllloorrrrrsss)))))))))) ssssssssssuuuuchh aaaaaaaaaassss pphhhooooooooottttooggggrrrrrrrrrraaaapppphhhhhhhhssssss,,,,,, aaaaaaaaalllllttttttttthhoouuuughhhhhh JJJJJJJPPPPEGGGGGGGGG uuussssssssessssssssss iiitttttt ooooooooonnnnnn tttttttttthhheeeee ccccoooooooeeeeefffffffffiiiiiiiiccccccieeeeeeeeennnnttssssssss tttttttthhhhhhhhatttttttttt rrrreeeemmmmmmmaaaaaaaiiiiiiiiiin aaaaafffttteeeeeerrr ttrrrrrrrraansssssssssffffffoooooooorrmmmmmmmmmmiiingggggggggg aaaaaannnnndddddddddd qqquuuaaaaaaannnnnnnnnnttttttttttiiiiiiiizziiiiiinnnnnnnggggggg iiiiiiiimaaaaaaaaaagggggge bbbllllooocccccccckkkkkkkksss....... Coooooooooommmmmmmmmmmmooooonnnnnnnnn fffffffffooooorrrrrrrrrmmmmmaaaaaaaatttttttttsssssssss foorrrrrrrr rrrruuuuuuuuuunnnnnnnnnn----lllllleeeeeeeeeenngggggggtttthhhh eeeeeeeeeencccccccccoooooooooddeeddddddddd ddddddaataa iiiiiiiiiinnnnnnnnccccluuuuudeeeeeeeeee TTTTTTTruuuueeeevvvvvvvvvviiiiiiisssssssiiiiiiiiionnnnnnnnnn TTTGGGGGGGGGAAAAA,,,,,,,, PPPPPPPPaaaaacccckkkkBBBBBBBiiitttsss ((((((((((bbby AAAAApppppppplleeeeeeee,,,,,,,,, uuuusssssseed iiiiiiiiiinn MMMMMaaaacccccccccPPPPPPPaaaaaaaaaiiinnnnttttttttt))))))), PPPPPPCCCCCCCCCCXX aaaaannnnnnnnnndddddd IIILLLLLLLLBBBBMMMMMMMMM..... TTTTTTThhhhhhhhe IIIIIInnnnnnnnnttteeerrnnnaaaaaaaaaatttttttttiiiiiiiooooooooonnnnnnnaaaaall TTTeeeeellleecccccoooooooommmmmmmmmuuuuuuuuunnniiiiiicccccccaaaaatttttttiiiiiiiiioooonnn UUUUUUUUUUnniioooooooooonn aaaaaaaallllsssssssssooooo deeessssssccccrrrrrrrrriiiiiiiiiibbbbbbbbbeeeeessssssss aa ssssssttttttttttaaaaaaannnnnddddddddarrrrrrrddddddddd toooooooo eeeeeennncccoooooooddddeeeeeeeeee rruunnnnn-lllllleeeeeeeeeennnnnnnngggggggggtthh cccccccooooolllllllloooooooorrrrrrrr ffffoooooorrrrr ffffffffffaaaaxxxx mmmmmaaccccccccchhhhhhhinnnnnnnnnessssssssss,, knnnnnnnoooooooooowwwwwwnnnnnnnnn aaaaaaaaass T..44455555........ TTTTTTTTTThhhhhhhhhhatt ffffffaxxxxxxxx ccoooollllllloooooooooorr cccooooodddddddddiiiiiiiiinngg sssssstaaaaaannnnnndaaarrrrrrrrrddddddddd,, wwwwwhhhhhhiiiiiiiccccccccchhhhhhh aaallooonnnnggg wwwwwwiiiittthh ooooooootttttttttthhhheeeeer tecccccccchhhhhhhhhhnnnniiiiqqquueeesssssss iiissssssss iiiiiiiinnnnnnnnnncccccccccoooorrrrrrppppppooooooooorrrrrraaaaaaaaatttteeedddddddd iiiiiiiiinnnnnnnnttto MMMMMMMooooooooodddifffffffiiiiiiiieeeeeeeeedddddddd HHHHHHHHHuuuuuuufffffffffmman coddinnnnnnnngg,,,, iiiissssssssss rrrrrreeelllatttttiiiiiiivvveeeeeeeeeellllllllyyyyy eeffffffffffffffiiiiiiiiccccccccciiiiiiiieeeeeeennnnnnnnntttttttttt bbbbbbeeeeeeeccccauuuuseee mmmmmmmmmoooosssssssstttttttt ffaxxxxxxxxeeeddddddddd dddddddoooccccuuuuuuuuuummmmmeeeeeeeennnnnnnnnntttttttts aaaaaarrrrrrrrrree pppprrrrrrrriiiiiimaaarrrrriiiiilllllllllyyyyyyyy wwwwwwwwhhhhhhhiiittttte ssspppppppaaaaacceeeeeeeee,,,,,, wwwwiiiiiithh oooooooooocccccccccccccccaasssssssiiiiiiooooonnnnnnnnnaaaaaaaalllllll iiinntttttttteeerrrrrrrruuuuuuppttttttttttiiooooooonnnnnnnnnnssssss ooooooooof bbbbbbbbbblllllllaaaaaaaaacccccckkkk...

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Hints

Hints will be released at the start of each of the following days - e.g. the start of day 3 is 48 hours after the challenge starts

Release Day	Hint
2	At minimum, will need a few important variables for this - the current consecutive count, the previous character, current character and the RLE result
3	Try with short strings first - think what you can initialise the current count to be with at the start so you can the correct count for the first character
4	We can loop through the string character by character - if the current character is equal to the previous character, we can increment the consecutive count - else, we should append the current count and previous character to the RLE string, then reset the current consecutive to 1 (not 0 - since assume we have "aaab" - once we have reached 'b', the count for 'b' should now be 1, not 0)
5	You will also have to make sure you output the ending characters too - they won't trigger an if statement that checks for a change between the current and previous character, so you can either have another condition in the if statement that appends to the RLE string if we are at the end of the string, or you can just do it once the loop ends