Solve p6, p9 in fortran

README.rst

@@ -85,7 +85,7 @@ Olivia's Project Euler Solutions
    |            |                            |        | |CodeQL| |br|     |
    |            |                            |        | |C#-lint|         |
    +------------+----------------------------+--------+-------------------+
-   | Fortran    | (In Progress)              |  3     | (In Progress)     |
+   | Fortran    | (In Progress)              |  5     | (In Progress)     |
    +------------+----------------------------+--------+-------------------+
    | Java       | Java 8+ in Corretto, |br|  | 22     | |Javai| |br|      |
    |            | Dragonwell, Liberica, |br| |        | |Ja-Cov| |br|     |

docs/index.rst

@@ -88,13 +88,13 @@ Problems Solved
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`005`|:c-d:`0005`|:cp-d:`0005`|:cs-d:`0005`|            |:ja-d:`0005`|:js-d:`0005`|:lu-d:`0005`|:py-d:`0005`|:rs-d:`0005`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
-  |:prob:`006`|:c-d:`0006`|:cp-d:`0006`|:cs-d:`0006`|            |:ja-d:`0006`|:js-d:`0006`|:lu-d:`0006`|:py-d:`0006`|:rs-d:`0006`|
+  |:prob:`006`|:c-d:`0006`|:cp-d:`0006`|:cs-d:`0006`|:fr-d:`0006`|:ja-d:`0006`|:js-d:`0006`|:lu-d:`0006`|:py-d:`0006`|:rs-d:`0006`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`007`|:c-d:`0007`|:cp-d:`0007`|:cs-d:`0007`|            |:ja-d:`0007`|:js-d:`0007`|:lu-d:`0007`|:py-d:`0007`|:rs-d:`0007`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`008`|:c-d:`0008`|:cp-d:`0008`|:cs-d:`0008`|            |:ja-d:`0008`|:js-d:`0008`|:lu-d:`0008`|:py-d:`0008`|:rs-d:`0008`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
-  |:prob:`009`|:c-d:`0009`|:cp-d:`0009`|:cs-d:`0009`|            |:ja-d:`0009`|:js-d:`0009`|:lu-d:`0009`|:py-d:`0009`|:rs-d:`0009`|
+  |:prob:`009`|:c-d:`0009`|:cp-d:`0009`|:cs-d:`0009`|:fr-d:`0009`|:ja-d:`0009`|:js-d:`0009`|:lu-d:`0009`|:py-d:`0009`|:rs-d:`0009`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`010`|:c-d:`0010`|:cp-d:`0010`|:cs-d:`0010`|            |:ja-d:`0010`|:js-d:`0010`|:lu-d:`0010`|:py-d:`0010`|:rs-d:`0010`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+

docs/src/fortran/p0006.rst

@@ -0,0 +1,18 @@
+Fortran Implementation of Problem 6
+===================================
+
+View source code :source:`fortran/src/p0006.for`
+
+.. f:module:: Problem0006
+
+.. f:function:: integer Problem0006/p0006()
+
+.. f:currentmodule::
+
+.. f:program:: test0006
+
+.. literalinclude:: ../../../fortran/src/p0006.for
+   :language: Fortran
+   :linenos:
+
+.. tags:: arithmetic-progression, sequence-summation

docs/src/fortran/p0009.rst

@@ -0,0 +1,18 @@
+Fortran Implementation of Problem 9
+===================================
+
+View source code :source:`fortran/src/p0009.for`
+
+.. f:module:: Problem0009
+
+.. f:function:: integer Problem0009/p0009()
+
+.. f:currentmodule::
+
+.. f:program:: test0009
+
+.. literalinclude:: ../../../fortran/src/p0009.for
+   :language: Fortran
+   :linenos:
+
+.. tags:: pythagorean-triple

fortran/README.rst

@@ -26,3 +26,6 @@ Problems Solved
 
 -  ☒ `1 <./src/p0001.for>`__
 -  ☒ `2 <./src/p0002.for>`__
+-  ☒ `6 <./src/p0006.for>`__
+-  ☒ `9 <./src/p0009.for>`__
+-  ☒ `836 <./src/p0836.for>`__

fortran/src/p0001.for

@@ -1,3 +1,14 @@
+! Project Euler Question 1
+!
+! I did it the old-fashioned way in this language
+!
+! Problem:
+!
+! If we list all the natural numbers below 10 that are multiples of 3 or 5, we
+! get 3, 5, 6 and 9. The sum of these multiples is 23.
+!
+! Find the sum of all the multiples of 3 or 5 below 1000.
+
 module Problem0001
     implicit none
 contains

fortran/src/p0002.for

@@ -1,3 +1,17 @@
+! Project Euler Problem 2
+!
+! I modeled this after the C++ solution, because it was by far the simplest
+!
+! Problem:
+!
+! Each new term in the Fibonacci sequence is generated by adding the previous two
+! terms. By starting with 1 and 2, the first 10 terms will be:
+!
+! 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
+!
+! By considering the terms in the Fibonacci sequence whose values do not exceed
+! four million, find the sum of the even-valued terms.
+
 module Problem0002
     implicit none
 contains

fortran/src/p0006.for

@@ -0,0 +1,42 @@
+! Project Euler Problem 6
+!
+! This turned out to be really easy
+!
+! Problem:
+!
+! The sum of the squares of the first ten natural numbers is,
+! 1**2 + 2**2 + ... + 10**2 = 385
+!
+! The square of the sum of the first ten natural numbers is,
+! (1 + 2 + ... + 10)**2 = 55**2 = 3025
+!
+! Hence the difference between the sum of the squares of the first ten natural
+! numbers and the square of the sum is 3025 − 385 = 2640.
+!
+! Find the difference between the sum of the squares of the first one hundred
+! natural numbers and the square of the sum.
+
+module Problem0006
+    implicit none
+contains
+    integer function p0006() result(answer)
+        integer :: sum
+        integer :: sum_of_squares
+        integer :: i
+        answer = 0
+        sum = 1
+        sum_of_squares = 1
+
+        do i = 2, 100
+            sum = sum + i
+            sum_of_squares = sum_of_squares + i * i
+        end do
+
+        answer = sum * sum - sum_of_squares
+    end function p0006
+end module Problem0006
+
+program test0006
+    use Problem0006
+    print *, p0006()
+end program test0006

fortran/src/p0009.for

@@ -0,0 +1,45 @@
+! Project Euler Problem 9
+!
+! This was pretty fun to port
+!
+! Problem:
+!
+! A Pythagorean triplet is a set of three natural numbers, a < b < c, for which,
+! a**2 + b**2 = c**2
+!
+! For example, 3**2 + 4**2 = 9 + 16 = 25 = 5**2.
+!
+! There exists exactly one Pythagorean triplet for which a + b + c = 1000.
+! Find the product abc.
+
+module Problem0009
+    implicit none
+contains
+    integer function p0009() result(answer)
+        integer :: a, b, c, a_square, b_square, c_square
+        c = 3
+
+        do
+            c_square = c * c
+
+            do b = 2, c
+                b_square = b * b
+
+                do a = 1, b
+                    a_square = a * a
+
+                    if (a_square + b_square == c_square .and. a + b + c == 1000) then
+                        answer = a * b * c
+                        return
+                    end if
+                end do
+            end do
+            c = c + 1
+        end do
+    end function p0009
+end module Problem0009
+
+program test0009
+    use Problem0009
+    print *, p0009()
+end program test0009

fortran/src/p0836.for

@@ -1,3 +1,18 @@
+! Project Euler Problem 836
+!
+! Alright, this was funny
+!
+! Problem:
+!
+! Let A be an **affine plane** over a **radically integral local field** F with residual characteristic p.
+!
+! We consider an **open oriented line section** U of A with normalized Haar measure m.
+!
+! Define f(m,p) as the maximal possible discriminant of the **jacobian** associated to the
+! **orthogonal kernel embedding** of U into A.
+!
+! Find f(20230401, 57). Give as your answer the concatenation of the first letters of each bolded word.
+
 module Problem0836
     implicit none
 contains