Part 1

Here's an easy puzzle to warm you up.

Santa is trying to deliver presents in a large apartment building, but he can't find the right floor - the directions he got are a little confusing. He starts on the ground floor (floor 0) and then follows the instructions one character at a time.

An opening parenthesis, (, means he should go up one floor, and a closing parenthesis, ), means he should go down one floor.

The apartment building is very tall, and the basement is very deep; he will never find the top or bottom floors.

For example:

(()) and ()() both result in floor 0.
((( and (()(()( both result in floor 3.
))((((( also results in floor 3.
()) and ))( both result in floor -1 (the first basement level).
))) and )())()) both result in floor -3.

To what floor do the instructions take Santa?

Loopy version of solution. Need to collect the contents of the input string to create an array of characters, then can use search on each of those items.



In [1]:

    
#collect("()()")
#search(") (", ")")
idx=0
for a in collect("()()")
    idx+= -2 + (search(") (", a))
end
println(idx)

Use a list comprehension to define a function.



In [2]:

    
floor(instructions) = sum([-2 + search(") (", a) for a in collect(instructions)])
println(floor("(())"))    # test 1 should equal 0
println(floor("))(((((")) # test 1 should equal 3



In [3]:

    
Day1_inp1 = "((((()(()(((((((()))(((()((((()())(())()(((()((((((()((()(()(((()(()((())))()((()()())))))))))()((((((())((()))(((((()(((((((((()()))((()(())()((())((()(()))((()))()))()(((((()(((()()))()())((()((((())()())()((((())()(()(()(((()(())(()(())(((((((())()()(((())(()(()(()(())))(()((((())((()))(((()(()()(((((()()(()(((()(((((())()))()((()(()))()((()((((())((((())(()(((())()()(()()()()()(())((((())((())(()()))()((((())))((((()())()((((())((()())((())(())(((((()((((()(((()((((())(()(((()()))()))((((((()((())()())))(((()(()))(()()(()(((()(()))((()()()())((()()()(((())())()())())())((()))(()(()))(((((()(()(())((()(())(())()((((()())()))((((())(())((())())((((()(((())(())((()()((((()((((((()(())()()(()(()()((((()))(())()())()))(())))(())))())()()(())(()))()((()(()(())()()))(()())))))(()))(()()))(())(((((()(()(()()((())()())))))((())())((())(()(())((()))(())(((()((((((((()()()(()))()()(((()))()((()()(())(())())()(()(())))(((((()(())(())(()))))())()))(()))()(()(((((((()((((())))())())())())()((((((((((((((()()((((((()()()())())()())())())(())(())))())((()())((()(()))))))()))))))))))))))))())((())((())()()))))))(((()((()(()()))((())(()()))()()())))(())))))))(()(((())))())()())))()()(())()))()(()))())((()()))))(()))))()))(()()(())))))))()(((()))))()(()))(())())))))()))((()))((()))())(())))))))))((((())()))()))()))())(())()()(())))())))(()())()))((()()(())))(())((((((()(())((()(((()(()()(())))()))))))()))()(()((()))()(()))(()(((())((((())())(())(()))))))))())))))))())())))))())))))()()(((())()(()))))))))())))))(())()()()))()))()))(()(())()()())())))))))())()(()(()))))()()()))))())(()))))()()))))()())))))(((())()()))(()))))))))))()()))))()()()))))(()())())()()())()(()))))()(()))(())))))))(((((())(())())()()))()()))(())))))()(()))))(())(()()))()())()))()))()))()))))())()()))())())))(()))(()))))))())()(((())()))))))))()))()())))())))())))()))))))))))()()))(()()))))))(())()(()))))())(()))))(()))))(()())))))())())()()))))())()))))))))(()))))()))))))()(()())))))))()))())))())))())))())))))))())(()()))))))(()())())))()())()))))))))))))))())))()(())))()))())()()(())(()()))(())))())()())(()(()(()))))())))))))))))())(()))()))()))))(())()())()())))))))))))()()))))))))))))())())))))(()())))))))))))())(())))()))))))))())())(()))()))(())))()))()()(())()))))))()((((())()))())())))))()))()))))((()())()))))())))(())))))))))))))))))()))))()()())()))()()))))())()))((()())))())))(()))(()())))))))()))()))))(())))))))(())))))())()()(()))())()))()()))))())()()))))())()))())))))))(()))))()())()))))))))(()))())))(()))()))))(())()))())())(())())())))))))((((())))))()))()))()())()(())))()))()))()())(()())()()(()())()))))())())))))(()))()))))())(()()(())))))(())()()((())())))))(())(())))))))())))))))))()(())))))))()())())())()(()))))))))(()))))))))())()()))()(()))))))()))))))())))))))(())))()()(())()())))))(((())))()((())()))())))(()()))())(())())))()(((()())))))()(()()())))()()(()()(()()))())()(()()()))())()()))()())(()))))())))))())))(())()()))))(()))))(())(()))(())))))()()))()))))())()))()()(())())))((()))())()))))))()()))))((()(()))))()()))))))())))))())(()((()())))))))))))()())())))()))(()))))))(()))(())()())))(()))))))))())()()()()))))(()())))))))((())))()))(()))(())(())()())()))))))))(())))())))(()))()()))(()()))(()))())))()(())))())((()((()(())))((())))()))))((((())())()())))(())))()))))))())(()()((())))())()(()())))))(()())()))())))))))((())())))))))(()(()))())()()(()()(((()(((()())))))()))))))()(())(()()((()()(())()()))())()())()))()())())())))))))(((())))))))()()))))))(((())()))(()()))(()()))))(()(()()((((())()())((()()))))(()(())))))()((()()()())()()((()((()()))(()))(((()()()))(((())))()(((())()))))))((()(())())))(()())(((((()(()))(()((()))(()())()))))(()(()))()(()))(())(((())(()()))))()()))(((()))))(()()()()))())))((()()()(())()))()))))()()))()))))))((((((()()()))))())((()()(((()))))(()(())(()()())())())))()(((()()))(())((())))(()))(()()()())((())())())(()))))()))()((()(())()(()()(())(()))(())()))(())(()))))(())(())())(()()(()((()()((())))((()))()((())))(((()()()()((((()))(()()))()()()(((())((())())(()()(()()()))()((())(())()))())(((()()(())))()((()()())()())(()(())())(((())(())())((())(())()(((()()))(())))((())(()())())(())((()()()((((((())))((()(((((())()))()))(())(()()))()))(())()()))(())((()()())()()(()))())()((())))()((()()())((((()())((())())())((()((()))()))((())((()()(()((()()(((())(()()))))((()((())()(((())(()((())())((())(()((((((())())()(()())()(())(((())((((((()(())(()((()()()((()()(()()()())))()()(((((()()))()((((((()))()(()(()(()(((()())((()))())()((()))(())))()))()()))())()()))())((((())(()(()))(((((((())(((()(((((()(((()()((((())(((())())))(()()()(()(()))()))((((((()))((()(((()(())((()((((()((((((())(((((())))(((()(()))))(((()(((())()((())(()((()))(((()()(((())((((()(()(((((()))(((()(((((((()(()()()(()(()(()()())(())(((((()(())())()())(()(()(()))()(()()()())(()()(()((()))()((())())()(()))((())(()))()(()))()(((()(()(()((((((()()()()())()(((((()()(((()()()((()(((((()))((((((((()()()(((((()))))))(()()()(())(()))(()()))))(())()))(((((()(((((()()(()(()())(((()))((((()((()(()(()((()(()((())))()(((()((()))((()))(((((((((()((()((()(())))()((((()((()()))((())(((()(((((()()(()(()()((()(()()()(((((((())())()())))))((((()()(()))()))(()((())()(()(((((((((()()(((()(()())(()((()())((())())((((()(((()(((()((((()((()((((()(()((((((())((((((((((((()()(()()((((((((((((((()((()()))()((((((((((((())((((()(()())((()(()(()))()(((((()()(((()()))()())(())((()(((((()((())(((((()((()(((((()))()()((((())()((((())(((((((((()(())(()(())))())(()((())(((())(())(())())(()(()(())()()((()((())()(((()(((((()(())))()(((()((())))((()()()(((()(((()((()(()(())(()((()())(()(()(((()(((((((((())(()((((()()))(()((((()()()()(((()((((((((()(()()((((((()(()()(()((()((((((((((()()(((((((()())(())))(((()()))(((((()((()()())(()()((((())((()((((()))))(())((()(()()(((()(()(((()((((()(((((()))())())(()((())()))(((()())((())((())((((()((()((((((())(()((((()()))((((((())()(()))((()(((())((((((((((()()(((((()(((((()((()()()((((())))(()))()((()(())()()((()((((((((((()((())(())(((((()(()(()()))((((()((((()()((()(((()(((((((((()(()((()((()))((((((()(((())()()((()(((((((()())))()()(()((()((()()(((()(()()()()((((()((())((((()(((((((((()(((()()(((()(()(((()(((()((())()(()((()(()(()(()))()(((()))(()((((()((())((((())((((((())(()))(()((((())((()(()((((((((()()((((((()(()(()()()(())((()((()()(((()(((((((()()((()(((((((()))(((((()(((()(()()()(()(((()((()()((())(()(((((((((()(()((()((((((()()((())()))(((((()((())()())()(((((((((((()))((((()()()()())(()()(()(()()))()))(()))(()(((()()))())(()(()))()()((())(()())()())()(()))()))(()()(()((((((())((()(((((((((((()(())()((()(()((()((()(()((()((((((((((()()())((())()(())))((())()())()(((((()(()())((((()((()(())(()))(((())()((()))(((((())(()))()()(()))(((())((((()((((()(())))(((((((()))))())()())(())((())()(()()((()(()))()(()()(()()((()())((())((()()))((((()))()()))(()()(())()()(((((()(())((()((((()))()))(()())())(((()()(()()))(())))))(()))((())(((((()((((()))()((((()))()((())(((())))(((()())))((()(()()((";
@time floor(Day1_inp1)









    



3
  





    Out[3]:





74






    



0.000126 seconds (152 allocations: 92.308 KB)



In [4]:

    
function getFloorNoLoop(text)
    mapreduce( (x) -> if x == "("; 1 elseif x == ")"; -1 else 0 end, +, 0, split(text,"") )
end
@time getFloorNoLoop(Day1_inp1)



In [5]:

    
function getFloorNoLoop2(text)
    mapreduce( (a) -> -2 + search(") (", a), +, 0, collect(text) )
end
@time getFloorNoLoop2(Day1_inp1)









    Out[5]:





74



In [6]:

    
using DataStructures
function getFloorCounting(instructions)
    instruct = counter(collect(instructions))
    instruct['('] - instruct[')']
end









    Out[6]:





getFloorCounting (generic function with 1 method)






    



0.042909 seconds (19.55 k allocations: 876.834 KB)
  0.041935 seconds (12.33 k allocations: 544.255 KB)



In [7]:

    
@time getFloorCounting(Day1_inp1)

Part 2

Now, given the same instructions, find the position of the first character that causes him to enter the basement (floor -1). The first character in the instructions has position 1, the second character has position 2, and so on.

For example:

) causes him to enter the basement at character position 1.
()()) causes him to enter the basement at character position 5.

What is the position of the character that causes Santa to first enter the basement?



In [8]:

    
function firstBmt(instructions)
    idx=0
    charpos=1
    for a in collect(instructions)
        idx+= -2 + (search(") (", a))
        if idx == -1 return charpos end
        charpos += 1    
    end
end









    Out[8]:





firstBmt (generic function with 1 method)

The above works and only does as much work as necessary. Feel like there should be a more elegant solution, possibly using Enumeration and perhaps a form of map or reduce?



In [9]:

    
function firstBmte(instructions)
    idx=0
    for a in enumerate(collect(instructions))
        idx+= -2 + (search(") (", a[2]))
        if idx == -1 return a[1] end
    end
end









    Out[9]:





firstBmte (generic function with 1 method)



In [16]:

    
@time firstBmte(Day1_inp1)









    



  





    Out[16]:





1795






    



0.000102 seconds (8 allocations: 27.594 KB)



In [14]:

    
#map( (x) -> -2 + search(") (",x), collect("((()))))"))
getFirstBasementEntranceComp(Instructions) = findfirst(cumsum([-2+search(") (", a) for a in collect(Instructions)]),-1)
@time getFirstBasementEntranceComp(Day1_inp1)









    



  





    Out[14]:





1795






    



0.039413 seconds (4.07 k allocations: 338.696 KB)



In [15]:

    
function getFirstBasementEntrance(text)
     findfirst( cumsum(map( (x) -> if x == '('; 1 elseif x == ')'; -1 else 0 end, collect(text) )), -1)
end
@time getFirstBasementEntrance(Day1_inp1)









    



  





    Out[15]:





1795






    



0.019474 seconds (609 allocations: 169.998 KB)