Solve p4, p34, p76 in lua

README.rst

@@ -93,7 +93,7 @@ Olivia's Project Euler Solutions
    |            | Browser [#]_               |        | |CodeQL| |br|     |
    |            |                            |        | |ESLint|          |
    +------------+----------------------------+--------+-------------------+
-   | Lua        | Lua 5+ [#]_                |  7     | |Luai| |br|       |
+   | Lua        | Lua 5+ [#]_                | 10     | |Luai| |br|       |
    |            |                            |        | |LuaCheck|        |
    +------------+----------------------------+--------+-------------------+
    | Python     | CPython 3.6+ |br|          | 80     | |Python| |br|     |

docs/index.rst

@@ -83,7 +83,7 @@ Problems Solved
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`003`|:c-d:`0003`|:cp-d:`0003`|:cs-d:`0003`|            |:js-d:`0003`|            |:py-d:`0003`|:rs-d:`0003`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
-  |:prob:`004`|:c-d:`0004`|:cp-d:`0004`|:cs-d:`0004`|:ja-d:`0004`|:js-d:`0004`|            |:py-d:`0004`|:rs-d:`0004`|
+  |:prob:`004`|:c-d:`0004`|:cp-d:`0004`|:cs-d:`0004`|:ja-d:`0004`|:js-d:`0004`|:lu-d:`0004`|:py-d:`0004`|:rs-d:`0004`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`005`|:c-d:`0005`|            |            |            |:js-d:`0005`|            |:py-d:`0005`|:rs-d:`0005`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
@@ -141,7 +141,7 @@ Problems Solved
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`033`|           |            |            |            |            |            |:py-d:`0033`|            |
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
-  |:prob:`034`|:c-d:`0034`|:cp-d:`0034`|:cs-d:`0034`|:ja-d:`0034`|:js-d:`0034`|            |:py-d:`0034`|:rs-d:`0034`|
+  |:prob:`034`|:c-d:`0034`|:cp-d:`0034`|:cs-d:`0034`|:ja-d:`0034`|:js-d:`0034`|:lu-d:`0034`|:py-d:`0034`|:rs-d:`0034`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`035`|           |            |            |            |:js-d:`0035`|            |:py-d:`0035`|:rs-s:`0035`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
@@ -205,7 +205,7 @@ Problems Solved
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`074`|           |            |            |            |            |            |:py-d:`0074`|            |
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
-  |:prob:`076`|:c-d:`0076`|:cp-d:`0076`|:cs-s:`0076`|:ja-d:`0076`|:js-s:`0076`|            |:py-d:`0076`|:rs-s:`0076`|
+  |:prob:`076`|:c-d:`0076`|:cp-d:`0076`|:cs-s:`0076`|:ja-d:`0076`|:js-s:`0076`|:lu-d:`0076`|:py-d:`0076`|:rs-s:`0076`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`077`|           |            |            |            |            |            |:py-d:`0077`|            |
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+

docs/src/lua/lib/math.rst

@@ -0,0 +1,13 @@
+math.lua
+========
+
+View source code :source:`lua/src/lib/math.lua`
+
+.. lua:function:: factorial(n)
+
+    :return: The factorial of n
+    :rtype: number
+
+.. literalinclude:: ../../../../lua/src/lib/math.lua
+   :language: Lua
+   :linenos:

docs/src/lua/lib/range.rst

@@ -3,7 +3,7 @@ range.lua
 
 View source code :source:`lua/src/lib/range.lua`
 
-This module directly ports some of the logic found in Python's :external:py:func:`range`.
+This module directly ports some of the logic found in Python's :external:py:obj:`range`.
 
 .. lua:function:: range_entry3(start, step, idx)
 

docs/src/lua/p0004.rst

@@ -0,0 +1,18 @@
+Lua Implementation of Problem 4
+===============================
+
+View source code :source:`lua/src/p0004.lua`
+
+Solution
+--------
+
+.. lua:function:: solution()
+
+    :return: The solution to problem 4
+    :rtype: number
+
+.. literalinclude:: ../../../lua/src/p0004.lua
+   :language: Lua
+   :linenos:
+
+.. tags:: palindrome

docs/src/lua/p0034.rst

@@ -0,0 +1,23 @@
+Lua Implementation of Problem 34
+================================
+
+View source code :source:`lua/src/p0034.lua`
+
+Includes
+--------
+
+- `math.lua <./lib/math.html>`__
+
+Solution
+--------
+
+.. lua:function:: solution()
+
+    :return: The solution to problem 34
+    :rtype: number
+
+.. literalinclude:: ../../../lua/src/p0034.lua
+   :language: Lua
+   :linenos:
+
+.. tags:: factorial, digit-sum

docs/src/lua/p0076.rst

@@ -0,0 +1,18 @@
+Lua Implementation of Problem 76
+================================
+
+View source code :source:`lua/src/p0076.lua`
+
+Solution
+--------
+
+.. lua:function:: solution()
+
+    :return: The solution to problem 76
+    :rtype: number
+
+.. literalinclude:: ../../../lua/src/p0076.lua
+   :language: Lua
+   :linenos:
+
+.. tags:: partition

lua/README.rst

@@ -57,8 +57,11 @@ Problems Solved
 
 -  ☒ `1 <./src/p0001.lua>`__
 -  ☒ `2 <./src/p0002.lua>`__
+-  ☒ `4 <./src/p0004.lua>`__
 -  ☒ `6 <./src/p0006.lua>`__
 -  ☒ `9 <./src/p0009.lua>`__
 -  ☒ `17 <./src/p0017.lua>`__
 -  ☒ `28 <./src/p0028.lua>`__
+-  ☒ `34 <./src/p0034.lua>`__
+-  ☒ `76 <./src/p0076.lua>`__
 -  ☒ `836 <./src/p0836.lua>`__

lua/src/lib/math.lua

@@ -0,0 +1,16 @@
+-- This file is a direct port of Python's range functions
+
+local function factorial(n)
+    local answer = 1
+
+    for i = 2,n,1
+    do
+        answer = answer * i
+    end
+
+    return answer
+end
+
+return {
+    factorial = factorial,
+}

lua/src/p0004.lua

@@ -0,0 +1,30 @@
+-- Project Euler Problem 4
+--
+-- Problem:
+--
+-- A palindromic number reads the same both ways. The largest palindrome made from
+-- the product of two 2-digit numbers is 9009 = 91 × 99.
+--
+-- Find the largest palindrome made from the product of two 3-digit numbers.
+
+return {
+    solution = function()
+        local answer = 0
+
+        for v = 101,1001,1
+        do
+            for u = 100,(v-1),1
+            do
+                local p = u * v
+                local ps = tostring(p)
+
+                if ps == ps.reverse() and p > answer
+                then
+                    answer = p
+                end
+            end
+        end
+
+        return answer
+    end
+}

lua/src/p0028.lua

@@ -48,7 +48,6 @@
 return {
     solution = function()
         local answer = 1
-        local range_entry = loadfile("src/lib/range.lua")().range_entry3
 
         for i = 1,(1000 / 2),1
         do
@@ -62,3 +61,5 @@ return {
         return answer
     end
 }
+
+local range_entry = loadfile("src/lib/range.lua")().range_entry3

lua/src/p0034.lua

@@ -0,0 +1,40 @@
+-- Project Euler Problem 34
+--
+-- This ended up being a filtering problem. The problem with my solution is that I
+-- am not satisfied with my filter at all. I feel like there is a more efficient
+-- way to go about it.
+--
+-- Problem:
+--
+-- 145 is a curious number, as 1! + 4! + 5! = 1 + 24 + 120 = 145.
+--
+-- Find the sum of all numbers which are equal to the sum of the factorial of
+-- their digits.
+--
+-- Note: as 1! = 1 and 2! = 2 are not sums they are not included.
+
+return {
+    solution = function()
+        local answer = 0
+
+        for x = 10,99999,1
+        do
+            local xs = tostring(x)
+            local sum = 0
+
+            for i = 1,xs.len(),1
+            do
+                sum = sum + factorial(tonumber(xs[i]))
+            end
+
+            if sum == x
+            do
+                answer = answer + 1
+            end
+        end
+
+        return answer
+    end
+}
+
+local factorial = loadfile('src/lib/math.lua')().factorial

lua/src/p0076.lua

@@ -0,0 +1,62 @@
+-- Project Euler Problem 34
+--
+-- This ended up being a filtering problem. The problem with my solution is that I
+-- am not satisfied with my filter at all. I feel like there is a more efficient
+-- way to go about it.
+--
+-- Problem:
+--
+-- 145 is a curious number, as 1! + 4! + 5! = 1 + 24 + 120 = 145.
+--
+-- Find the sum of all numbers which are equal to the sum of the factorial of
+-- their digits.
+--
+-- Note: as 1! = 1 and 2! = 2 are not sums they are not included.
+
+return {
+    solution = function()
+        local answer = 0
+        local idx = 0
+        local sum = 100
+        local counts = {}
+
+        for i = 1, 101 do
+            counts[i] = 0
+        end
+
+        counts[2 + 1] = 0
+
+        while counts[100 + 1] == 0
+        do
+            counts[2 + 1] = counts[2 + 1] + 2
+
+            if sum >= 100
+            then
+                answer = answer + (100 + counts[2 + 1] - sum) / 2
+                idx = 2
+
+                repeat
+                    idx = idx + 1
+                    counts[idx] = 0  -- please remember lua is 1-indexed
+                    idx = idx + 1
+                    counts[idx] = counts[idx] + idx - 1
+
+                    for i = (idx - 1),101,1
+                    do
+                        sum = sum + counts[i]
+                    end
+                until sum <= 100
+            end
+
+            sum = 0
+            for i = 1,101,1
+            do
+                sum = sum + counts[i]
+            end
+        end
+
+        return answer
+    end
+}
+
+local factorial = loadfile('src/lib/math.lua')().factorial

lua/test.lua

@@ -46,10 +46,13 @@ end
 local problems = {
     ["p0001.lua"] = {233168, 60},
     ["p0002.lua"] = {4613732, 60},
+    ["p0004.lua"] = {906609, 60},
     ["p0006.lua"] = {25164150, 60},
     ["p0009.lua"] = {31875000, 60},
     ["p0017.lua"] = {21124, 60},
     ["p0028.lua"] = {669171001, 60},
+    ["p0034.lua"] = {40730, 60},
+    ["p0076.lua"] = {190569291, 60},
     ["p0836.lua"] = {"aprilfoolsjoke", 60},
 }