From 750d811b1d1956e3e7797bbcc7099ccd4619de7b Mon Sep 17 00:00:00 2001
From: Eric Willigers <keiravillekode@gmail.com>
Date: Sat, 13 Jul 2024 13:31:59 +1000
Subject: [PATCH] Add largest-series-product exercise

---
 config.json                                   |   8 +
 .../.docs/instructions.append.md              |   9 ++
 .../.docs/instructions.md                     |  26 ++++
 .../.docs/introduction.md                     |   5 +
 .../practice/largest-series-product/.eslintrc |  18 +++
 .../largest-series-product/.meta/config.json  |  28 ++++
 .../largest-series-product/.meta/proof.ci.wat |  77 ++++++++++
 .../largest-series-product/.meta/tests.toml   |  60 ++++++++
 .../practice/largest-series-product/.npmrc    |   1 +
 .../practice/largest-series-product/LICENSE   |  21 +++
 .../largest-series-product/babel.config.js    |   4 +
 .../largest-series-product.spec.js            | 142 ++++++++++++++++++
 .../largest-series-product.wat                |  15 ++
 .../largest-series-product/package.json       |  34 +++++
 14 files changed, 448 insertions(+)
 create mode 100644 exercises/practice/largest-series-product/.docs/instructions.append.md
 create mode 100644 exercises/practice/largest-series-product/.docs/instructions.md
 create mode 100644 exercises/practice/largest-series-product/.docs/introduction.md
 create mode 100644 exercises/practice/largest-series-product/.eslintrc
 create mode 100644 exercises/practice/largest-series-product/.meta/config.json
 create mode 100644 exercises/practice/largest-series-product/.meta/proof.ci.wat
 create mode 100644 exercises/practice/largest-series-product/.meta/tests.toml
 create mode 100644 exercises/practice/largest-series-product/.npmrc
 create mode 100644 exercises/practice/largest-series-product/LICENSE
 create mode 100644 exercises/practice/largest-series-product/babel.config.js
 create mode 100644 exercises/practice/largest-series-product/largest-series-product.spec.js
 create mode 100644 exercises/practice/largest-series-product/largest-series-product.wat
 create mode 100644 exercises/practice/largest-series-product/package.json

diff --git a/config.json b/config.json
index 8b3a299..53bc7cb 100644
--- a/config.json
+++ b/config.json
@@ -223,6 +223,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "largest-series-product",
+        "name": "Largest Series Product",
+        "uuid": "2534388c-96ef-45f7-a4e2-eb830dfb9c66",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "sieve",
         "name": "Sieve of Eratosthenes",
diff --git a/exercises/practice/largest-series-product/.docs/instructions.append.md b/exercises/practice/largest-series-product/.docs/instructions.append.md
new file mode 100644
index 0000000..9c9b521
--- /dev/null
+++ b/exercises/practice/largest-series-product/.docs/instructions.append.md
@@ -0,0 +1,9 @@
+# Instruction append
+
+If the input is invalid, return `-1`.
+
+## Reserved Memory
+
+The buffer for the input string uses bytes 64-319 of linear memory.
+
+The input string can be modified if desired.
diff --git a/exercises/practice/largest-series-product/.docs/instructions.md b/exercises/practice/largest-series-product/.docs/instructions.md
new file mode 100644
index 0000000..f297b57
--- /dev/null
+++ b/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**.
diff --git a/exercises/practice/largest-series-product/.docs/introduction.md b/exercises/practice/largest-series-product/.docs/introduction.md
new file mode 100644
index 0000000..597bb5f
--- /dev/null
+++ b/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.
diff --git a/exercises/practice/largest-series-product/.eslintrc b/exercises/practice/largest-series-product/.eslintrc
new file mode 100644
index 0000000..1dbeac2
--- /dev/null
+++ b/exercises/practice/largest-series-product/.eslintrc
@@ -0,0 +1,18 @@
+{
+  "root": true,
+  "extends": "@exercism/eslint-config-javascript",
+  "env": {
+    "jest": true
+  },
+  "overrides": [
+    {
+      "files": [
+        "*.spec.js"
+      ],
+      "excludedFiles": [
+        "custom.spec.js"
+      ],
+      "extends": "@exercism/eslint-config-javascript/maintainers"
+    }
+  ]
+}
diff --git a/exercises/practice/largest-series-product/.meta/config.json b/exercises/practice/largest-series-product/.meta/config.json
new file mode 100644
index 0000000..45fc387
--- /dev/null
+++ b/exercises/practice/largest-series-product/.meta/config.json
@@ -0,0 +1,28 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "largest-series-product.wat"
+    ],
+    "test": [
+      "largest-series-product.spec.js"
+    ],
+    "example": [
+      ".meta/proof.ci.wat"
+    ],
+    "invalidator": [
+      "package.json"
+    ]
+  },
+  "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",
+  "custom": {
+    "version.tests.compatibility": "jest-27",
+    "flag.tests.task-per-describe": false,
+    "flag.tests.may-run-long": false,
+    "flag.tests.includes-optional": false
+  }
+}
diff --git a/exercises/practice/largest-series-product/.meta/proof.ci.wat b/exercises/practice/largest-series-product/.meta/proof.ci.wat
new file mode 100644
index 0000000..07525fc
--- /dev/null
+++ b/exercises/practice/largest-series-product/.meta/proof.ci.wat
@@ -0,0 +1,77 @@
+(module
+  (memory (export "mem") 1)
+
+  (global $ZERO i32 (i32.const 48))
+
+  ;;
+  ;; Calculate the largest product for a contiguous substring of digits of length n.
+  ;;
+  ;; @param {i32} offset - offset of string in linear memory
+  ;; @param {i32} length - length of string in linear memory
+  ;;
+  ;; @returns {i32} largest digit product
+  ;;
+  (func (export "largestProduct") (param $offset i32) (param $length i32) (param $span i32) (result i32)
+    (local $product i32)
+    (local $stop i32)
+    (local $start i32)
+    (local $result i32)
+    (local $index i32)
+    (local $digit i32)
+
+    (if (i32.or (i32.lt_s (local.get $span) (i32.const 0))
+                (i32.gt_s (local.get $span) (local.get $length))) (then
+      (return (i32.const -1))
+    ))
+
+    (if (i32.eqz (local.get $length)) (then
+      (return (i32.const 1))
+    ))
+
+    (local.set $stop (i32.add (local.get $offset) (local.get $length)))
+
+    (local.set $index (local.get $offset))
+    (loop
+      (local.set $digit (i32.sub (i32.load8_u (local.get $index))
+                                 (global.get $ZERO)))
+      (if (i32.gt_u (local.get $digit) (i32.const 9)) (then
+        ;; $digit is not a valid digit.
+        (return (i32.const -1))
+      ))
+      (i32.store8 (local.get $index) (local.get $digit))
+
+      (local.set $index (i32.add (local.get $index) (i32.const 1)))
+      (br_if 0 (i32.lt_u (local.get $index) (local.get $stop)))
+    )
+
+    (if (i32.eqz (local.get $span)) (then
+      (return (i32.const 1))
+    ))
+
+    (local.set $result (i32.const 0))
+
+    (local.set $start (i32.sub (local.get $stop) (local.get $span)))
+    (loop $outer
+      (local.set $product (i32.const 1))
+      (local.set $index (local.get $start))
+      (loop $inner
+        (local.set $product (i32.mul (local.get $product)
+                                     (i32.load8_u (local.get $index))))
+        (local.set $index (i32.add (local.get $index) (i32.const 1)))
+        (br_if $inner (i32.lt_u (local.get $index) (local.get $stop)))
+      )
+      (if (i32.lt_u (local.get $result) (local.get $product)) (then
+        (local.set $result (local.get $product))
+      ))
+
+      (if (i32.eq (local.get $start) (local.get $offset)) (then
+        (return (local.get $result))
+      ))
+
+      (local.set $start (i32.sub (local.get $start) (i32.const 1)))
+      (local.set $stop (i32.sub (local.get $stop) (i32.const 1)))
+      (br $outer)
+    )
+    (unreachable)
+  )
+)
diff --git a/exercises/practice/largest-series-product/.meta/tests.toml b/exercises/practice/largest-series-product/.meta/tests.toml
new file mode 100644
index 0000000..6c111ad
--- /dev/null
+++ b/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"
diff --git a/exercises/practice/largest-series-product/.npmrc b/exercises/practice/largest-series-product/.npmrc
new file mode 100644
index 0000000..d26df80
--- /dev/null
+++ b/exercises/practice/largest-series-product/.npmrc
@@ -0,0 +1 @@
+audit=false
diff --git a/exercises/practice/largest-series-product/LICENSE b/exercises/practice/largest-series-product/LICENSE
new file mode 100644
index 0000000..90e73be
--- /dev/null
+++ b/exercises/practice/largest-series-product/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Exercism
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/exercises/practice/largest-series-product/babel.config.js b/exercises/practice/largest-series-product/babel.config.js
new file mode 100644
index 0000000..9c17ba5
--- /dev/null
+++ b/exercises/practice/largest-series-product/babel.config.js
@@ -0,0 +1,4 @@
+export default {
+  presets: ["@exercism/babel-preset-javascript"],
+  plugins: [],
+};
diff --git a/exercises/practice/largest-series-product/largest-series-product.spec.js b/exercises/practice/largest-series-product/largest-series-product.spec.js
new file mode 100644
index 0000000..74aa882
--- /dev/null
+++ b/exercises/practice/largest-series-product/largest-series-product.spec.js
@@ -0,0 +1,142 @@
+import { compileWat, WasmRunner } from "@exercism/wasm-lib";
+
+let wasmModule;
+let currentInstance;
+
+function largestProduct(input = "", span) {
+  const inputBufferOffset = 64;
+  const inputBufferCapacity = 256;
+
+  const inputLengthEncoded = new TextEncoder().encode(input).length;
+  if (inputLengthEncoded > inputBufferCapacity) {
+    throw new Error(
+      `String is too large for buffer of size ${inputBufferCapacity} bytes`
+    );
+  }
+
+  currentInstance.set_mem_as_utf8(inputBufferOffset, inputLengthEncoded, input);
+
+  // Pass offset and length to WebAssembly function
+  return currentInstance.exports.largestProduct(
+    inputBufferOffset,
+    inputLengthEncoded,
+    span
+  );
+}
+
+beforeAll(async () => {
+  try {
+    const watPath = new URL("./largest-series-product.wat", import.meta.url);
+    const { buffer } = await compileWat(watPath);
+    wasmModule = await WebAssembly.compile(buffer);
+  } catch (err) {
+    console.log(`Error compiling *.wat: \n${err}`);
+    process.exit(1);
+  }
+});
+
+describe("largestProduct()", () => {
+  beforeEach(async () => {
+    currentInstance = null;
+    if (!wasmModule) {
+      return Promise.reject();
+    }
+    try {
+      currentInstance = await new WasmRunner(wasmModule);
+      return Promise.resolve();
+    } catch (err) {
+      console.log(`Error instantiating WebAssembly module: ${err}`);
+      return Promise.reject();
+    }
+  });
+
+  test("finds the largest product if span equals length", () => {
+    const expected = 18;
+    const actual = largestProduct("29", 2);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("can find the largest product of 2 with numbers in order", () => {
+    const expected = 72;
+    const actual = largestProduct("0123456789", 2);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("can find the largest product of 2", () => {
+    const expected = 48;
+    const actual = largestProduct("576802143", 2);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("can find the largest product of 3 with numbers in order", () => {
+    const expected = 504;
+    const actual = largestProduct("0123456789", 3);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("can find the largest product of 3", () => {
+    const expected = 270;
+    const actual = largestProduct("1027839564", 3);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("can find the largest product of 5 with numbers in order", () => {
+    const expected = 15120;
+    const actual = largestProduct("0123456789", 5);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("can get the largest product of a big number", () => {
+    const expected = 23520;
+    const actual = largestProduct("73167176531330624919225119674426574742355349194934", 6);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("reports zero if the only digits are zero", () => {
+    const expected = 0;
+    const actual = largestProduct("0000", 2);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("reports zero if all spans include zero", () => {
+    const expected = 0;
+    const actual = largestProduct("99099", 3);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("rejects span longer than string length", () => {
+    const expected = -1;
+    const actual = largestProduct("123", 4);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("reports 1 for empty string and empty product (0 span)", () => {
+    const expected = 1;
+    const actual = largestProduct("", 0);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("reports 1 for nonempty string and empty product (0 span)", () => {
+    const expected = 1;
+    const actual = largestProduct("123", 0);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("rejects empty string and nonzero span", () => {
+    const expected = -1;
+    const actual = largestProduct("", 1);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("rejects invalid character in digits", () => {
+    const expected = -1;
+    const actual = largestProduct("1234a5", 2);
+    expect(actual).toEqual(expected);
+  });
+
+  xtest("rejects negative span", () => {
+    const expected = -1;
+    const actual = largestProduct("12345", -1);
+    expect(actual).toEqual(expected);
+  });
+});
diff --git a/exercises/practice/largest-series-product/largest-series-product.wat b/exercises/practice/largest-series-product/largest-series-product.wat
new file mode 100644
index 0000000..5cbdfc6
--- /dev/null
+++ b/exercises/practice/largest-series-product/largest-series-product.wat
@@ -0,0 +1,15 @@
+(module
+  (memory (export "mem") 1)
+
+  ;;
+  ;; Calculate the largest product for a contiguous substring of digits of length n.
+  ;;
+  ;; @param {i32} offset - offset of string in linear memory
+  ;; @param {i32} length - length of string in linear memory
+  ;;
+  ;; @returns {i32} largest digit product
+  ;;
+  (func (export "largestProduct") (param $offset i32) (param $length i32) (param $span i32) (result i32)
+    (return (i32.const 0))
+  )
+)
diff --git a/exercises/practice/largest-series-product/package.json b/exercises/practice/largest-series-product/package.json
new file mode 100644
index 0000000..5a523ba
--- /dev/null
+++ b/exercises/practice/largest-series-product/package.json
@@ -0,0 +1,34 @@
+{
+  "name": "@exercism/wasm-largest-series-product",
+  "description": "Exercism exercises in WebAssembly.",
+  "type": "module",
+  "private": true,
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/exercism/wasm",
+    "directory": "exercises/practice/largest-series-product"
+  },
+  "jest": {
+    "maxWorkers": 1
+  },
+  "devDependencies": {
+    "@babel/core": "^7.23.3",
+    "@exercism/babel-preset-javascript": "^0.4.0",
+    "@exercism/eslint-config-javascript": "^0.6.0",
+    "@types/jest": "^29.5.8",
+    "@types/node": "^20.9.1",
+    "babel-jest": "^29.7.0",
+    "core-js": "^3.33.2",
+    "eslint": "^8.54.0",
+    "jest": "^29.7.0"
+  },
+  "dependencies": {
+    "@exercism/wasm-lib": "^0.2.0"
+  },
+  "scripts": {
+    "test": "node --experimental-vm-modules node_modules/jest/bin/jest.js ./*",
+    "watch": "node --experimental-vm-modules node_modules/jest/bin/jest.js --watch ./*",
+    "lint": "eslint ."
+  }
+}