[largest-series-product] Implementation

config.json

@@ -481,7 +481,16 @@
         "prerequisites": [],
         "difficulty": 1,
         "topics": []
-      }      
+      },
+      {
+        "slug": "largest-series-product",
+        "name": "Largest Series Product",
+        "uuid": "762a6196-6185-46d1-aa97-0c245db8e981",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1,
+        "topics": []
+      }
     ]
   },
   "concepts": [],

exercises/practice/largest-series-product/.docs/instructions.md

@@ -0,0 +1,26 @@
+# Instructions
+
+Your task is to look for patterns in the long sequence of digits in the encrypted signal.
+
+The technique you're going to use here is called the largest series product.
+
+Let's define a few terms, first.
+
+- **input**: the sequence of digits that you need to analyze
+- **series**: a sequence of adjacent digits (those that are next to each other) that is contained within the input
+- **span**: how many digits long each series is
+- **product**: what you get when you multiply numbers together
+
+Let's work through an example, with the input `"63915"`.
+
+- To form a series, take adjacent digits in the original input.
+- If you are working with a span of `3`, there will be three possible series:
+  - `"639"`
+  - `"391"`
+  - `"915"`
+- Then we need to calculate the product of each series:
+  - The product of the series `"639"` is 162 (`6 × 3 × 9 = 162`)
+  - The product of the series `"391"` is 27 (`3 × 9 × 1 = 27`)
+  - The product of the series `"915"` is 45 (`9 × 1 × 5 = 45`)
+- 162 is bigger than both 27 and 45, so the largest series product of `"63915"` is from the series `"639"`.
+  So the answer is **162**.

exercises/practice/largest-series-product/.docs/introduction.md

@@ -0,0 +1,5 @@
+# Introduction
+
+You work for a government agency that has intercepted a series of encrypted communication signals from a group of bank robbers.
+The signals contain a long sequence of digits.
+Your team needs to use various digital signal processing techniques to analyze the signals and identify any patterns that may indicate the planning of a heist.

exercises/practice/largest-series-product/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "habere-et-dispertire"
+  ],
+  "files": {
+    "solution": [
+      "LargestSeriesProduct.rakumod"
+    ],
+    "test": [
+      "largest-series-product.rakutest"
+    ],
+    "example": [
+      ".meta/solutions/LargestSeriesProduct.rakumod"
+    ]
+  },
+  "blurb": "Given a string of digits, calculate the largest product for a contiguous substring of digits of length n.",
+  "source": "A variation on Problem 8 at Project Euler",
+  "source_url": "https://projecteuler.net/problem=8"
+}

exercises/practice/largest-series-product/.meta/solutions/LargestSeriesProduct.rakumod

@@ -0,0 +1,11 @@
+proto largest-product (|) is export {*}
+multi largest-product ( $n, 0 ) { 1 }
+multi largest-product ( $n, Int $span where 1 .. $n.chars ) {
+
+    $n
+    .comb
+    .rotor( $span => - $span.pred )
+    .map(          *.reduce: &[*] )
+    .max
+
+}

exercises/practice/largest-series-product/.meta/solutions/largest-series-product.rakutest

@@ -0,0 +1 @@
+../../largest-series-product.rakutest

exercises/practice/largest-series-product/.meta/template-data.yaml

@@ -0,0 +1,38 @@
+properties:
+  largestProduct:
+    test: |-
+      if %case<expected><error>:exists {
+        sprintf(q:to/END/, (%case<input><digits>, %case<input><span>, %case<description>).map(*.raku));
+        dies-ok(
+            { largest-product(%s, %s) },
+            %s,
+        );
+        END
+      }
+      else {
+        sprintf(q:to/END/, (%case<input><digits>, %case<input><span>, %case<expected>, %case<description>).map(*.raku));
+        cmp-ok(
+            largest-product(%s, %s),
+            &infix:<==>,
+            %s,
+            %s,
+        );
+        END
+      }
+
+example: |-
+  proto largest-product (|) is export {*}
+  multi largest-product ( $n, 0 ) { 1 }
+  multi largest-product ( $n, Int $span where 1 .. $n.chars ) {
+
+      $n
+      .comb
+      .rotor( $span => - $span.pred )
+      .map(          *.reduce: &[*] )
+      .max
+
+  }
+
+stub: |-
+  sub largest-product ($number, $span) is export {
+  }

exercises/practice/largest-series-product/.meta/tests.toml

@@ -0,0 +1,60 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[7c82f8b7-e347-48ee-8a22-f672323324d4]
+description = "finds the largest product if span equals length"
+
+[88523f65-21ba-4458-a76a-b4aaf6e4cb5e]
+description = "can find the largest product of 2 with numbers in order"
+
+[f1376b48-1157-419d-92c2-1d7e36a70b8a]
+description = "can find the largest product of 2"
+
+[46356a67-7e02-489e-8fea-321c2fa7b4a4]
+description = "can find the largest product of 3 with numbers in order"
+
+[a2dcb54b-2b8f-4993-92dd-5ce56dece64a]
+description = "can find the largest product of 3"
+
+[673210a3-33cd-4708-940b-c482d7a88f9d]
+description = "can find the largest product of 5 with numbers in order"
+
+[02acd5a6-3bbf-46df-8282-8b313a80a7c9]
+description = "can get the largest product of a big number"
+
+[76dcc407-21e9-424c-a98e-609f269622b5]
+description = "reports zero if the only digits are zero"
+
+[6ef0df9f-52d4-4a5d-b210-f6fae5f20e19]
+description = "reports zero if all spans include zero"
+
+[5d81aaf7-4f67-4125-bf33-11493cc7eab7]
+description = "rejects span longer than string length"
+
+[06bc8b90-0c51-4c54-ac22-3ec3893a079e]
+description = "reports 1 for empty string and empty product (0 span)"
+
+[3ec0d92e-f2e2-4090-a380-70afee02f4c0]
+description = "reports 1 for nonempty string and empty product (0 span)"
+
+[6d96c691-4374-4404-80ee-2ea8f3613dd4]
+description = "rejects empty string and nonzero span"
+
+[7a38f2d6-3c35-45f6-8d6f-12e6e32d4d74]
+description = "rejects invalid character in digits"
+
+[5fe3c0e5-a945-49f2-b584-f0814b4dd1ef]
+description = "rejects negative span"
+include = false
+
+[c859f34a-9bfe-4897-9c2f-6d7f8598e7f0]
+description = "rejects negative span"
+reimplements = "5fe3c0e5-a945-49f2-b584-f0814b4dd1ef"

exercises/practice/largest-series-product/LargestSeriesProduct.rakumod

@@ -0,0 +1,2 @@
+sub largest-product ($number, $span) is export {
+}

exercises/practice/largest-series-product/largest-series-product.rakutest

@@ -0,0 +1,103 @@
+#!/usr/bin/env raku
+use Test;
+use lib $?FILE.IO.dirname;
+use LargestSeriesProduct;
+
+cmp-ok( # begin: 7c82f8b7-e347-48ee-8a22-f672323324d4
+    largest-product("29", 2),
+    &infix:<==>,
+    18,
+    "finds the largest product if span equals length",
+); # end: 7c82f8b7-e347-48ee-8a22-f672323324d4
+
+cmp-ok( # begin: 88523f65-21ba-4458-a76a-b4aaf6e4cb5e
+    largest-product("0123456789", 2),
+    &infix:<==>,
+    72,
+    "can find the largest product of 2 with numbers in order",
+); # end: 88523f65-21ba-4458-a76a-b4aaf6e4cb5e
+
+cmp-ok( # begin: f1376b48-1157-419d-92c2-1d7e36a70b8a
+    largest-product("576802143", 2),
+    &infix:<==>,
+    48,
+    "can find the largest product of 2",
+); # end: f1376b48-1157-419d-92c2-1d7e36a70b8a
+
+cmp-ok( # begin: 46356a67-7e02-489e-8fea-321c2fa7b4a4
+    largest-product("0123456789", 3),
+    &infix:<==>,
+    504,
+    "can find the largest product of 3 with numbers in order",
+); # end: 46356a67-7e02-489e-8fea-321c2fa7b4a4
+
+cmp-ok( # begin: a2dcb54b-2b8f-4993-92dd-5ce56dece64a
+    largest-product("1027839564", 3),
+    &infix:<==>,
+    270,
+    "can find the largest product of 3",
+); # end: a2dcb54b-2b8f-4993-92dd-5ce56dece64a
+
+cmp-ok( # begin: 673210a3-33cd-4708-940b-c482d7a88f9d
+    largest-product("0123456789", 5),
+    &infix:<==>,
+    15120,
+    "can find the largest product of 5 with numbers in order",
+); # end: 673210a3-33cd-4708-940b-c482d7a88f9d
+
+cmp-ok( # begin: 02acd5a6-3bbf-46df-8282-8b313a80a7c9
+    largest-product("73167176531330624919225119674426574742355349194934", 6),
+    &infix:<==>,
+    23520,
+    "can get the largest product of a big number",
+); # end: 02acd5a6-3bbf-46df-8282-8b313a80a7c9
+
+cmp-ok( # begin: 76dcc407-21e9-424c-a98e-609f269622b5
+    largest-product("0000", 2),
+    &infix:<==>,
+    0,
+    "reports zero if the only digits are zero",
+); # end: 76dcc407-21e9-424c-a98e-609f269622b5
+
+cmp-ok( # begin: 6ef0df9f-52d4-4a5d-b210-f6fae5f20e19
+    largest-product("99099", 3),
+    &infix:<==>,
+    0,
+    "reports zero if all spans include zero",
+); # end: 6ef0df9f-52d4-4a5d-b210-f6fae5f20e19
+
+dies-ok( # begin: 5d81aaf7-4f67-4125-bf33-11493cc7eab7
+    { largest-product("123", 4) },
+    "rejects span longer than string length",
+); # end: 5d81aaf7-4f67-4125-bf33-11493cc7eab7
+
+cmp-ok( # begin: 06bc8b90-0c51-4c54-ac22-3ec3893a079e
+    largest-product("", 0),
+    &infix:<==>,
+    1,
+    "reports 1 for empty string and empty product (0 span)",
+); # end: 06bc8b90-0c51-4c54-ac22-3ec3893a079e
+
+cmp-ok( # begin: 3ec0d92e-f2e2-4090-a380-70afee02f4c0
+    largest-product("123", 0),
+    &infix:<==>,
+    1,
+    "reports 1 for nonempty string and empty product (0 span)",
+); # end: 3ec0d92e-f2e2-4090-a380-70afee02f4c0
+
+dies-ok( # begin: 6d96c691-4374-4404-80ee-2ea8f3613dd4
+    { largest-product("", 1) },
+    "rejects empty string and nonzero span",
+); # end: 6d96c691-4374-4404-80ee-2ea8f3613dd4
+
+dies-ok( # begin: 7a38f2d6-3c35-45f6-8d6f-12e6e32d4d74
+    { largest-product("1234a5", 2) },
+    "rejects invalid character in digits",
+); # end: 7a38f2d6-3c35-45f6-8d6f-12e6e32d4d74
+
+dies-ok( # begin: c859f34a-9bfe-4897-9c2f-6d7f8598e7f0
+    { largest-product("12345", -1) },
+    "rejects negative span",
+); # end: c859f34a-9bfe-4897-9c2f-6d7f8598e7f0
+
+done-testing;