How to resolve the algorithm Dinesman's multiple-dwelling problem step by step in the Lua programming language

Published on 12 May 2024 09:40 PM
#Lua

How to resolve the algorithm Dinesman's multiple-dwelling problem step by step in the Lua programming language

Table of Contents

Problem Statement

Solve Dinesman's multiple dwelling problem but in a way that most naturally follows the problem statement given below. Solutions are allowed (but not required) to parse and interpret the problem text, but should remain flexible and should state what changes to the problem text are allowed. Flexibility and ease of expression are valued. Examples may be be split into "setup", "problem statement", and "output" sections where the ease and naturalness of stating the problem and getting an answer, as well as the ease and flexibility of modifying the problem are the primary concerns. Example output should be shown here, as well as any comments on the examples flexibility.

Baker, Cooper, Fletcher, Miller, and Smith live on different floors of an apartment house that contains only five floors.

Where does everyone live?

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Dinesman's multiple-dwelling problem step by step in the Lua programming language

Source code in the lua programming language

local wrap, yield = coroutine.wrap, coroutine.yield
local function perm(n)
    local r = {}
    for i=1,n do r[i]=i end    
  return wrap(function()
    local function swap(m)      
      if m==0 then  
        yield(r)
      else
        for i=m,1,-1 do
          r[i],r[m]=r[m],r[i]
          swap(m-1)
          r[i],r[m]=r[m],r[i]
        end    
      end
    end
    swap(n)
  end)
end

local function iden(...)return ... end
local function imap(t,f)
  local r,fn = {m=imap, c=table.concat, u=table.unpack}, f or iden
  for i=1,#t do r[i]=fn(t[i])end
  return r
end

local tenants = {'Baker', 'Cooper', 'Fletcher', 'Miller', 'Smith'}

local conds = {
  'Baker  ~= TOP',
  'Cooper ~= BOTTOM',
  'Fletcher ~= TOP and Fletcher~= BOTTOM',
  'Miller > Cooper',
  'Smith + 1 ~= Fletcher and Smith - 1 ~= Fletcher',
  'Cooper + 1 ~= Fletcher and Cooper - 1 ~= Fletcher',
}

local function makePredicate(conds, tenants)
  return load('return function('..imap(tenants):c','..
    ') return ' ..
    imap(conds,function(c)
      return string.format("(%s)",c) 
    end):c"and "..
    " end ",'-',nil,{TOP=5, BOTTOM=1})()
end

local function solve (conds, tenants)
  local try, pred, upk = perm(#tenants), makePredicate(conds, tenants), table.unpack
  local answer = try()
  while answer and not pred(upk(answer)) do answer = try()end
  if answer then
    local floor = 0
    return imap(answer, function(person) 
        floor=floor+1; 
        return string.format(" %s lives on floor %d",tenants[floor],person) 
    end):c"\n"
  else
    return nil, 'no solution'
  end  
end

print(solve (conds, tenants))

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