Solve p18, p67 in js

LivInTheLookingGlass · Sep 3, 2024 · e7954b7 · e7954b7
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diff --git a/README.rst b/README.rst
@@ -78,7 +78,7 @@ Olivia's Project Euler Solutions
 |            | Microsoft, Oracle, |br|    |        | |CodeQL| |br|     |
 |            | Semeru, Temurin, & Zulu    |        | |Java-lint|       |
 +------------+----------------------------+--------+-------------------+
-| JavaScript | Node 12+ |br|              | 30     | |JavaScript| |br| |
+| JavaScript | Node 12+ |br|              | 32     | |JavaScript| |br| |
 |            | Bun 1.0+ |br|              |        | |Js-Cov| |br|     |
 |            | Browser [#]_               |        | |CodeQL| |br|     |
 |            |                            |        | |ESLint|          |

diff --git a/docs/index.rst b/docs/index.rst
@@ -110,7 +110,7 @@ Problems Solved
 +-----------+------------+------------+------------+------------+------------+------------+------------+
 |:prob:`17` |:c-d:`0017` |:cp-d:`0017`|:cs-d:`0017`|:ja-d:`0017`|:js-d:`0017`|:py-d:`0017`|:rs-d:`0017`|
 +-----------+------------+------------+------------+------------+------------+------------+------------+
-|:prob:`18` |            |            |            |            |            |:py-d:`0018`|:rs-d:`0018`|
+|:prob:`18` |            |            |            |            |:js-d:`0018`|:py-d:`0018`|:rs-d:`0018`|
 +-----------+------------+------------+------------+------------+------------+------------+------------+
 |:prob:`19` |:c-d:`0019` |:cp-d:`0019`|:cs-d:`0019`|:ja-d:`0019`|:js-d:`0019`|:py-d:`0019`|:rs-d:`0019`|
 +-----------+------------+------------+------------+------------+------------+------------+------------+
@@ -192,7 +192,7 @@ Problems Solved
 +-----------+------------+------------+------------+------------+------------+------------+------------+
 |:prob:`63` |            |            |            |            |            |:py-d:`0063`|            |
 +-----------+------------+------------+------------+------------+------------+------------+------------+
-|:prob:`67` |            |            |            |            |            |:py-d:`0067`|:rs-d:`0067`|
+|:prob:`67` |            |            |            |            |:js-d:`0067`|:py-d:`0067`|:rs-d:`0067`|
 +-----------+------------+------------+------------+------------+------------+------------+------------+
 |:prob:`69` |            |            |            |            |            |:py-d:`0069`|:rs-d:`0069`|
 +-----------+------------+------------+------------+------------+------------+------------+------------+

diff --git a/docs/src/javascript/lib/triangles.rst b/docs/src/javascript/lib/triangles.rst
@@ -0,0 +1,10 @@
+triangles.js
+============
+
+View source code :source:`javascript/src/lib/triangles.js`
+
+.. js:autofunction:: triangles.reduceTriangle
+
+.. literalinclude:: ../../../../javascript/src/lib/triangles.js
+   :language: javascript
+   :linenos:
diff --git a/docs/src/javascript/p0018.rst b/docs/src/javascript/p0018.rst
@@ -0,0 +1,12 @@
+JavaScript Implementation of Problem 18
+=======================================
+
+View source code :source:`javascript/src/p0018.js`
+
+.. js:autofunction:: p0018
+
+.. literalinclude:: ../../../javascript/src/p0018.js
+   :language: javascript
+   :linenos:
+
+.. tags:: combinatorics, path-finding
diff --git a/docs/src/javascript/p0067.rst b/docs/src/javascript/p0067.rst
@@ -0,0 +1,12 @@
+JavaScript Implementation of Problem 67
+=======================================
+
+View source code :source:`javascript/src/p0067.js`
+
+.. js:autofunction:: p0067
+
+.. literalinclude:: ../../../javascript/src/p0067.js
+   :language: javascript
+   :linenos:
+
+.. tags:: combinatorics, path-finding, file-io
diff --git a/javascript/README.rst b/javascript/README.rst
@@ -116,6 +116,7 @@ Problems Solved
 -  ☒ `15 <./src/p0015.js>`__
 -  ☒ `16 <./src/p0016.js>`__
 -  ☒ `17 <./src/p0017.js>`__
+-  ☒ `18 <./src/p0019.js>`__
 -  ☒ `19 <./src/p0019.js>`__
 -  ☒ `20 <./src/p0020.js>`__
 -  ☒ `22 <./src/p0022.js>`__
@@ -127,5 +128,6 @@ Problems Solved
 -  ☒ `41 <./src/p0041.js>`__
 -  ☒ `46 <./src/p0046.js>`__
 -  ☒ `60 <./src/p0060.js>`__
+-  ☒ `67 <./src/p0067.js>`__
 -  ☒ `76 <./src/p0076.js>`__
 -  ☒ `836 <./src/p0836.js>`__
diff --git a/javascript/euler.test.js b/javascript/euler.test.js
@@ -40,6 +40,8 @@ const answers = {
     15: [require('./src/p0015.js'), false],
     16: [require('./src/p0016.js'), false],
     17: [require('./src/p0017.js'), false],
+    18: [require('./src/p0018.js'), false],
+    19: [require('./src/p0019.js'), false],
     20: [require('./src/p0020.js'), false],
     22: [require('./src/p0022.js'), false],
     23: [require('./src/p0023.js'), false],
@@ -50,6 +52,7 @@ const answers = {
     41: [require('./src/p0041.js'), false],
     46: [require('./src/p0046.js'), false],
     60: [require('./src/p0060.js'), false],
+    67: [require('./src/p0067.js'), false],
     836: [require('./src/p0836.js'), false],
     76: [require('./src/p0076.js'), true],
 };

diff --git a/javascript/src/lib/triangles.js b/javascript/src/lib/triangles.js
@@ -0,0 +1,18 @@
+/**
+ * Compute the factorial of a given number. Note that, unlike the version of this in other languages, this does not
+ * guard against imprecision or overflow.
+ * @param {Array<Array<number>>} triangle
+ * @return {number}
+ */
+exports.reduceTriangle = function reduceTriangle(triangle) {
+    centering = triangle[triangle.length - 1].length + 1;
+    const potentialTotals = new Array(centering).fill(0);
+    const _triangle = Array.from(triangle);
+    _triangle.reverse();
+    for (const parent of _triangle) {
+        for (let i = 0; i < parent.length; i++) {
+            potentialTotals[i] = Math.max(potentialTotals[i], potentialTotals[i + 1]) + parent[i];
+        }
+    }
+    return potentialTotals[0];
+};
diff --git a/javascript/src/p0018.js b/javascript/src/p0018.js
@@ -0,0 +1,67 @@
+/**
+ * Project Euler Problem 18
+ *
+ * Thinking from the bottom up got the answer
+ *
+ * Problem:
+ *
+ * By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from
+ * top to bottom is 23.
+ *
+ * .. code-block::
+ *
+ *      3
+ *     7 4
+ *    2 4 6
+ *   8 5 9 3
+ *
+ * That is, 3 + 7 + 4 + 9 = 23.
+ *
+ * Find the maximum total from top to bottom of the triangle below:
+ *
+ * .. code-block::
+ *
+ *                               75
+ *                             95  64
+ *                           17  47  82
+ *                         18  35  87  10
+ *                       20  04  82  47  65
+ *                     19  01  23  75  03  34
+ *                   88  02  77  73  07  63  67
+ *                 99  65  04  28  06  16  70  92
+ *               41  41  26  56  83  40  80  70  33
+ *             41  48  72  33  47  32  37  16  94  29
+ *           53  71  44  65  25  43  91  52  97  51  14
+ *         70  11  33  28  77  73  17  78  39  68  17  57
+ *       91  71  52  38  17  14  91  43  58  50  27  29  48
+ *     63  66  04  68  89  53  67  30  73  16  69  87  40  31
+ *   04  62  98  27  23  09  70  98  73  93  38  53  60  04  23
+ *
+ * NOTE: As there are only 16384 routes, it is possible to solve this problem by trying every route. However, Problem
+ * 67, is the same challenge with a triangle containing one-hundred rows; it cannot be solved by brute force, and
+ * requires a clever method! ;o)
+ *
+ * @return {number}
+ */
+exports.p0018 = function() {
+    const rows = [
+        [75],
+        [95, 64],
+        [17, 47, 82],
+        [18, 35, 87, 10],
+        [20, 4, 82, 47, 65],
+        [19, 1, 23, 75, 3, 34],
+        [88, 2, 77, 73, 7, 63, 67],
+        [99, 65, 4, 28, 6, 16, 70, 92],
+        [41, 41, 26, 56, 83, 40, 80, 70, 33],
+        [41, 48, 72, 33, 47, 32, 37, 16, 94, 29],
+        [53, 71, 44, 65, 25, 43, 91, 52, 97, 51, 14],
+        [70, 11, 33, 28, 77, 73, 17, 78, 39, 68, 17, 57],
+        [91, 71, 52, 38, 17, 14, 91, 43, 58, 50, 27, 29, 48],
+        [63, 66, 4, 68, 89, 53, 67, 30, 73, 16, 69, 87, 40, 31],
+        [4, 62, 98, 27, 23, 9, 70, 98, 73, 93, 38, 53, 60, 4, 23],
+    ];
+    return triangles.reduceTriangle(rows);
+};
+
+const triangles = require('./lib/triangles.js');
diff --git a/javascript/src/p0067.js b/javascript/src/p0067.js
@@ -0,0 +1,36 @@
+/**
+ * Project Euler Problem 67
+ *
+ * Thinking from the bottom up got the answer
+ *
+ * Problem:
+ *
+ * By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from
+ * top to bottom is 23.
+ *
+ * 3
+ * 7 4
+ * 2 4 6
+ * 8 5 9 3
+ *
+ * That is, 3 + 7 + 4 + 9 = 23.
+ *
+ * Find the maximum total from top to bottom in triangle.txt (right click and 'Save Link/Target As...'), a 15K text file
+ * containing a triangle with one-hundred rows.
+ *
+ * NOTE: This is a much more difficult version of Problem 18. It is not possible to try every route to solve this
+ * problem, as there are 2^99 altogether! If you could check one trillion (10^12) routes every second it would take
+ * over twenty billion years to check them all. There is an efficient algorithm to solve it. ;o)
+ *
+ * @return {number}
+ */
+exports.p0067 = function() {
+    const rows = [];
+    for (const line of utils.get_data_file('p0067_triangle.txt').trim().split(/\r?\n|\r|\n/g)) {
+        rows.push(line.split(' ').map(Number));
+    }
+    return triangles.reduceTriangle(rows);
+};
+
+const triangles = require('./lib/triangles.js');
+const utils = require('./lib/utils.js');
diff --git a/rust/src/problems/p0018.rs b/rust/src/problems/p0018.rs
@@ -1,5 +1,5 @@
 /*
-Project Euler Problem 67
+Project Euler Problem 18
 
 Thinking from the bottom up got the answer
 
@@ -8,19 +8,38 @@ Problem:
 By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from top
 to bottom is 23.
 
-3
-7 4
-2 4 6
-8 5 9 3
+.. code-block::
+
+     3
+    7 4
+   2 4 6
+  8 5 9 3
 
 That is, 3 + 7 + 4 + 9 = 23.
 
-Find the maximum total from top to bottom in triangle.txt (right click and 'Save Link/Target As...'), a 15K text file
-containing a triangle with one-hundred rows.
+Find the maximum total from top to bottom of the triangle below:
+
+.. code-block::
+
+                              75
+                            95  64
+                          17  47  82
+                        18  35  87  10
+                      20  04  82  47  65
+                    19  01  23  75  03  34
+                  88  02  77  73  07  63  67
+                99  65  04  28  06  16  70  92
+              41  41  26  56  83  40  80  70  33
+            41  48  72  33  47  32  37  16  94  29
+          53  71  44  65  25  43  91  52  97  51  14
+        70  11  33  28  77  73  17  78  39  68  17  57
+      91  71  52  38  17  14  91  43  58  50  27  29  48
+    63  66  04  68  89  53  67  30  73  16  69  87  40  31
+  04  62  98  27  23  09  70  98  73  93  38  53  60  04  23
 
-NOTE: This is a much more difficult version of Problem 18. It is not possible to try every route to solve this problem,
-as there are 2^99 altogether! If you could check one trillion (10^12) routes every second it would take over twenty
-billion years to check them all. There is an efficient algorithm to solve it. ;o)
+NOTE: As there are only 16384 routes, it is possible to solve this problem by trying every route. However, Problem 67,
+is the same challenge with a triangle containing one-hundred rows; it cannot be solved by brute force, and requires a
+clever method! ;o)
 */
 use crate::include::triangles::reduce_triangle;
 use crate::include::utils::Answer;