Solve p26 in python

README.rst

@@ -107,7 +107,7 @@ Olivia's Project Euler Solutions
    |            |                            |        | |Lu-Cov| |br|     |
    |            |                            |        | |LuaCheck|        |
    +------------+----------------------------+--------+-------------------+
-   | Python     | CPython 3.6+ |br|          | 80     | |Python| |br|     |
+   | Python     | CPython 3.6+ |br|          | 81     | |Python| |br|     |
    |            | Pypy 3.6+ |br|             |        | |Py-Cov| |br|     |
    |            | GraalPy 23.1+ |br|         |        | |CodeQL| |br|     |
    |            | Browser [#]_               |        | |PythonLint|      |

docs/index.rst

@@ -128,6 +128,8 @@ Problems Solved
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`025`|:c-d:`0025`|            |            |            |            |            |            |:py-d:`0025`|:rs-d:`0025`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
+  |:prob:`026`|           |            |            |            |            |            |            |:py-d:`0026`|            |
+  +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`027`|           |            |            |            |            |:js-d:`0027`|            |:py-d:`0027`|:rs-s:`0027`|
   +-----------+-----------+------------+------------+------------+------------+------------+------------+------------+------------+
   |:prob:`028`|           |            |            |:fr-d:`0028`|            |:js-d:`0028`|:lu-d:`0028`|:py-d:`0028`|:rs-d:`0028`|

docs/src/python/p0026.rst

@@ -0,0 +1,14 @@
+Python Implementation of Problem 26
+===================================
+
+View source code :source:`python/src/p0026.py`
+
+.. automodule:: python.src.p0026
+   :members:
+   :undoc-members:
+
+.. literalinclude:: ../../../python/src/p0026.py
+   :language: python
+   :linenos:
+
+.. tags:: fraction, recurring-decimal, decimal-representation

python/README.rst

@@ -152,6 +152,7 @@ Problems Solved
 -  ☒ `23 <./src/p0023.py>`__
 -  ☒ `24 <./src/p0024.py>`__
 -  ☒ `25 <./src/p0025.py>`__
+-  ☒ `26 <./src/p0026.py>`__
 -  ☒ `27 <./src/p0027.py>`__
 -  ☒ `28 <./src/p0028.py>`__
 -  ☒ `29 <./src/p0029.py>`__

python/src/p0026.py

@@ -0,0 +1,38 @@
+"""
+Project Euler Problem 26
+
+Problem:
+
+A unit fraction contains 1 in the numerator. The decimal representation of the unit fractions with denominators 2 to 10 are given:
+
+.. code-block::
+
+    1/2 = 0.5
+    1/3 = 0.(3)
+    1/4 = 0.25
+    1/5 = 0.2
+    1/6 = 0.1(6)
+    1/7 = 0.(142857)
+    1/8 = 0.125
+    1/9 = 0.(1)
+    1/10 = 0.1
+
+Where 0.1(6) means 0.166666\cdots, and has a 1-digit recurring cycle. It can be seen that 1/7 has a 6-digit recurring cycle.
+Find the value of d < 1000 for which 1/d contains the longest recurring cycle in its decimal fraction part.
+
+"""
+
+
+def main() -> int:
+    remainders = {d: [1] for d in range(2, 1000)}
+    cycle_lengths = {}
+    while len(remainders):
+        for d in tuple(remainders.keys()):
+            base = 10 * remainders[d][-1]
+            rem = base % d
+            if rem in remainders[d]:
+                cycle_lengths[d] = len(remainders[d]) - remainders[d].index(rem)
+                del remainders[d]
+            else:
+                remainders[d].append(rem)
+    return max(cycle_lengths.items(), key=lambda p: p[1])[0]

python/test_euler.py

@@ -19,8 +19,7 @@
 
 answers: Dict[int, Union[int, str]] = {
     x: get_answer(x) for x in (
-        *range(1, 26),
-        *range(27, 51),
+        *range(1, 51),
         52,
         53,
         *range(55, 61),