Advent of code Day 21

In [6]:

    

library(foreach)
library(stringr)
library(binhf)


    

In [2]:

    

input <- readLines("data.txt")


    

In [3]:

    

password <- c('a','b','c','d','e','f','g','h')
#password <- c('a','b','c','d','e')
a <- foreach(i=input) %do% {
    cmd <- str_split(i," ")[[1]]
    switch(paste(c(cmd[[1]],cmd[[2]]),collapse=""), 
        swapposition={
           tmp <- password[[as.integer(cmd[[3]])+1]]            
           password[[as.integer(cmd[[3]])+1]] <- password[[as.integer(cmd[[6]])+1]]
           password[[as.integer(cmd[[6]])+1]] <- tmp
      #  print(password)
        },
        swapletter={
            tmp <- cmd[[3]]
            tmp2 <- cmd[[6]]
            password <- str_replace(password, cmd[[3]], 'X')
            password <- str_replace(password, cmd[[6]], tmp)
            password <- str_replace(password, 'X', tmp2) 
      #  print(password) 
        },
        reversepositions={
            from <- as.integer(cmd[[3]])+1
            to <- as.integer(cmd[[5]])+1
            password[from:to] <- rev(password[from:to])
       # print(password) 
        },
        rotateleft={
            password <- shift(password,as.integer(cmd[[3]]),dir = "left")
      #  print(password) 
        },
        rotateright={
            password <- shift(password,as.integer(cmd[[3]]),dir = "right")
       # print(password) 
        },
        moveposition={
            from <- as.integer(cmd[[3]])+1
            to <- as.integer(cmd[[6]])
            tmp <- password[[from]]
            password <- append(password[-from],tmp,to)
        #print(password) 
        },
        rotatebased={
        value <-  which(password == cmd[[7]]) - 1
        value <- value + if(value >= 4) 2 else 1
      #  print(value)
        password <- shift(password, value%%length(password), dir = "right")
       # print(password) 
        },
        {
           print('default')
        }
    )
       # print(paste(password,collapse=""))
    
}
Q1 <- paste(password,collapse="")


    

In [4]:

    

password <- c('f','b','g','d','c','e','a','h')
#password <- c('a','b','c','d','e')
#paste(password,collapse="")
a <- foreach(i=rev(input)) %do% {
    cmd <- str_split(i," ")[[1]]
    switch(paste(c(cmd[[1]],cmd[[2]]),collapse=""), 
        swapposition={
           tmp <- password[[as.integer(cmd[[3]])+1]]            
           password[[as.integer(cmd[[3]])+1]] <- password[[as.integer(cmd[[6]])+1]]
           password[[as.integer(cmd[[6]])+1]] <- tmp
      #  print(password)
        },
        swapletter={
            tmp <- cmd[[3]]
            tmp2 <- cmd[[6]]
            password <- str_replace(password, cmd[[3]], 'X')
            password <- str_replace(password, cmd[[6]], tmp)
            password <- str_replace(password, 'X', tmp2) 
      #  print(password) 
        },
        reversepositions={
            from <- as.integer(cmd[[3]])+1
            to <- as.integer(cmd[[5]])+1
            password[from:to] <- rev(password[from:to])
       # print(password) 
        },
        rotateleft={
            password <- shift(password,as.integer(cmd[[3]]),dir = "right")
      #  print(password) 
        },
        rotateright={
            password <- shift(password,as.integer(cmd[[3]]),dir = "left")
       # print(password) 
        },
        moveposition={
            from <- as.integer(cmd[[6]])+1
            to <- as.integer(cmd[[3]])
            tmp <- password[[from]]
            password <- append(password[-from],tmp,to)
        #print(password) 
        },
        rotatebased={
            tmp <- password
            while(TRUE){
                password <- shift(password, 1, dir = "left")
                value <-  which(password == cmd[[7]]) - 1
                value <- value + if(value >= 4) 2 else 1
                if(all(shift(password, value%%length(password), dir = "right")==tmp))
                    break
                       
            }
        },
        {
           print('default')
        }
    )
        #print(paste(password,collapse=""))
}
Q2 <- paste(password,collapse="")
Q2


    

    





"bcfaegdh"

In [5]:

    

cat("Q1- The first password is : ", Q1, '\n')
cat("Q2- The original input for the second password is : ", Q2, '\n')


    

    




Q1- The first password is :  gbhafcde 
Q2- The original input for the second password is :  bcfaegdh