Added 100 doors problem

Author: Yonaba

100_Doors_Problem/Lua/Yonaba/100doors.lua

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+-- 100 doors problem implementation
+-- See : http://rosettacode.org/wiki/100_doors
+
+-- Collects keys of values matching a predicate
+local function collect(t, v)
+  local s = {}
+  for k,_v in ipairs(t) do
+    if _v == v then s[#s+1] = k end
+  end
+  return s
+end
+
+-- Simulates the 100 doors problem
+-- returns : a table of all open doors
+--           a table of all closed doors
+local function hundred_doors()
+  local doors = {}
+  for mp = 1, 100 do
+    for i = mp, 100, mp  do
+      doors[i] = (doors[i] == nil and false or not doors[i])
+    end
+  end
+  return collect(doors, true), collect(doors, false)
+end
+
+return hundred_doors

100_Doors_Problem/Lua/Yonaba/100doors_test.lua

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+-- Tests for 100doors.lua
+local hundred_doors = require '100doors'
+
+local total, pass = 0, 0
+
+local function dec(str, len)
+  return #str < len
+     and str .. (('.'):rep(len-#str))
+      or str:sub(1,len)
+end
+
+local function run(message, f)
+  total = total + 1
+  local ok, err = pcall(f)
+  if ok then pass = pass + 1 end
+  local status = ok and 'PASSED' or 'FAILED'
+  print(('%02d. %68s: %s'):format(total, dec(message,68), status))
+end
+
+run('Open doors are perfect squares of integers', function()
+  local open, closed = hundred_doors()
+  for i, v in ipairs(open) do
+    assert(math.floor(math.sqrt(v)) == math.sqrt(v))
+  end
+end)
+
+print(('-'):rep(80))
+print(('Total : %02d: Pass: %02d - Failed : %02d - Success: %.2f %%')
+  :format(total, pass, total-pass, (pass*100/total)))

100_Doors_Problem/tags

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+Puzzle