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Advent of code Day 4

Ref: http://adventofcode.com/2016/day/4





In [1]:



    


library(foreach)
library(stringr)



    











In [2]:



    


data <- readLines("data.txt")
str(data)



    


















    






 chr [1:935] "vxupkizork-sgmtkzoi-pkrrehkgt-zxgototm-644[kotgr]" ...

















In [15]:



    


ttt <- str_match(data,"(.*)\\-+(\\d+)\\[(.*)\\]")
head(ttt)



    


















    









	
vxupkizork-sgmtkzoi-pkrrehkgt-zxgototm-644[kotgr]vxupkizork-sgmtkzoi-pkrrehkgt-zxgototm           644                                              kotgr                                            

	
mbiyqoxsm-pvygob-nocsqx-900[obmqs]mbiyqoxsm-pvygob-nocsqx           900                               obmqs                             

	
veqtekmrk-ikk-hitpscqirx-334[nrtws]veqtekmrk-ikk-hitpscqirx           334                                nrtws                              

	
gvcskirmg-fyrrc-irkmriivmrk-932[rikmc]gvcskirmg-fyrrc-irkmriivmrk           932                                   rikmc                                 

	
xmtjbzidx-xviyt-yzqzgjkhzio-187[yzfeu]xmtjbzidx-xviyt-yzqzgjkhzio           187                                   yzfeu                                 

	
bwx-amkzmb-kivlg-kwibqvo-lmaqov-798[bkmva]bwx-amkzmb-kivlg-kwibqvo-lmaqov           798                                       bkmva

Parsing string with regex





In [3]:



    


parsedData <- gsub("(.*)\\-+(\\d+)\\[(.*)\\]", '\\1:\\2:\\3', data, perl = TRUE)
parsedData <- strsplit(parsedData, ':')
head(parsedData)



    


















    







    
	
    1. 
	
    1. "vxupkizork-sgmtkzoi-pkrrehkgt-zxgototm"
      2. 
	
    2. "644"
      3. 
	
    3. "kotgr"
      4. 

    

    2. 
	
    2. 
	
    1. "mbiyqoxsm-pvygob-nocsqx"
      2. 
	
    2. "900"
      3. 
	
    3. "obmqs"
      4. 

    

    3. 
	
    3. 
	
    1. "veqtekmrk-ikk-hitpscqirx"
      2. 
	
    2. "334"
      3. 
	
    3. "nrtws"
      4. 

    

    4. 
	
    4. 
	
    1. "gvcskirmg-fyrrc-irkmriivmrk"
      2. 
	
    2. "932"
      3. 
	
    3. "rikmc"
      4. 

    

    5. 
	
    5. 
	
    1. "xmtjbzidx-xviyt-yzqzgjkhzio"
      2. 
	
    2. "187"
      3. 
	
    3. "yzfeu"
      4. 

    

    6. 
	
    6. 
	
    1. "bwx-amkzmb-kivlg-kwibqvo-lmaqov"
      2. 
	
    2. "798"
      3. 
	
    3. "bkmva"
      4. 

    

    7.

Turn into a dataframe





In [4]:



    


dataf <-  as.data.frame(matrix(unlist(parsedData), ncol = 3, byrow=T))
colnames(dataf)<- c("code","value","checksum")
head(dataf)



    


















    









codevaluechecksum


	
1vxupkizork-sgmtkzoi-pkrrehkgt-zxgototm644                                   kotgr                                 

	
2mbiyqoxsm-pvygob-nocsqx900                    obmqs                  

	
3veqtekmrk-ikk-hitpscqirx334                     nrtws                   

	
4gvcskirmg-fyrrc-irkmriivmrk932                        rikmc                      

	
5xmtjbzidx-xviyt-yzqzgjkhzio187                        yzfeu                      

	
6bwx-amkzmb-kivlg-kwibqvo-lmaqov798                            bkmva

Create new column that process the checksum





In [5]:



    


# Simple parsing in int of the value column
dataf$value <- strtoi(dataf$value, base = 0L)



    











In [6]:



    


dataf$Valid <- apply(dataf, 1, function(x) {
    a<-(sort(table(strsplit(gsub("-","",x[1]),"")), decreasing = TRUE)[1:5])
    paste(attributes(a)$dimnames[[1]], collapse = '') == x[3]
})



    











In [7]:



    


sum(dataf$value) # Complete Sum
sum(dataf$value[dataf$Valid]) #Sum when Valid



    


















    






511391









    






137896

Create Caesar Cipher

Stolen with pride from: https://github.com/johnmyleswhite/JuliaVsR/blob/master/cipher/cipher.R





In [8]:



    


english.letters <- c('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k',
                     'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
                     'w', 'x', 'y', 'z')

caesar.cipher <- list()

for (index in 1:length(english.letters))
{
  caesar.cipher[[english.letters[index]]] <- english.letters[index %% 26 + 1]
}
caesar.cipher[['-']] <- '-'



    











In [9]:



    


apply.cipher.to.string <- function(string, cipher)
{
  output <- ''

  for (i in 1:nchar(string))
  {
  output <- paste(output, cipher[[substr(string, i, i)]], sep = '')
  }
  
  return(output)
}



    











In [10]:



    


tmp <- "northpole-object-storage"
possible <- foreach(x=1:26) %do% {
    tmp <- apply.cipher.to.string(tmp, caesar.cipher)
    #intersect(strsplit(tmp,'-')[[1]], words)
    #if( intersect(strsplit(tmp,'-')[[1]], words) != "")
      #  strsplit(tmp,'-')[[1]][1]
}
dataf$value[dataf$code==intersect(possible,dataf$code)]



    


















    






501

Answers





In [11]:



    


paste("Q1 -- Number of good room is ", sum(dataf$value[dataf$Valid]))
paste("Q2 -- Value of the north pole storage room is ", dataf$value[dataf$code==intersect(possible,dataf$code)])



    


















    






"Q1 -- Number of good room is  137896"









    






"Q2 -- Value of the north pole storage room is  501"

Help

I used that to search all possible word to end up with northpole-object-storage





In [12]:



    


#words <- readLines("words.txt")



    











In [13]:



    


#a <- apply(dataf, 1, function(x) {
#    output <- ""
#    tmp <-x[1]
#    possible <- foreach(x=1:26) %do% {
#        tmp <- apply.cipher.to.string(tmp, caesar.cipher)
#        #intersect(strsplit(tmp,'-')[[1]], words)
#        if(sum((intersect(strsplit(tmp,'-')[[1]], words)) != "")>0)
#            output <- tmp
#    }
#    output
#})
#    a

Content source: marcolivierarsenault/AdventOfCode2016

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