new exercise: word-search

Added a new Exercise per issue #238

config.json

@@ -275,6 +275,22 @@
         "unicode"
       ]
     },
+    {
+      "slug": "word-search",
+      "uuid": "8ba2c83e-f544-11e9-802a-5aa538984bd8",
+      "core": false,
+      "unlocked_by": "linked-list",
+      "difficulty": 8,
+      "topics": [
+        "arrays",
+        "conditionals",
+        "loops",
+        "equality",
+        "optional_values",
+        "parsing",
+        "text_formatting"
+      ]
+    },
     {
       "slug": "difference-of-squares",
       "uuid": "3f649490-dc7d-4a77-a2a0-2ae71ae834a9",

exercises/word-search/.eslintignore

@@ -0,0 +1,8 @@
+bin/*
+dist/*
+docs/*
+node_modules/*
+production_node_modules/*
+test/fixtures/*
+tmp/*
+jest.config.js

exercises/word-search/.eslintrc

@@ -0,0 +1,64 @@
+{
+  "root": true,
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "project": "./tsconfig.json",
+    "ecmaFeatures": {
+      "jsx": true
+    },
+    "ecmaVersion": 2018,
+    "sourceType": "module"
+  },
+  "env": {
+    "browser": true,
+    "es6": true
+  },
+  "extends": [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/eslint-recommended",
+    "plugin:@typescript-eslint/recommended",
+  ],
+  "globals": {
+    "Atomics": "readonly",
+    "SharedArrayBuffer": "readonly"
+  },
+  "plugins": [
+    "@typescript-eslint"
+  ],
+  "rules": {
+    "@typescript-eslint/array-type": "off", // Styling not forced upon the student
+    "@typescript-eslint/explicit-function-return-type": [
+      "warn", {
+        "allowExpressions": false,
+        "allowTypedFunctionExpressions": true,
+        "allowHigherOrderFunctions": true
+      }
+    ], // Prevent bugs
+    "@typescript-eslint/explicit-member-accessibility": "off", // Styling not forced upon the student
+    "@typescript-eslint/indent": "off", // Styling not forced upon the student
+    "@typescript-eslint/no-inferrable-types": [
+      "error", {
+        "ignoreParameters": true
+      }
+    ],
+    "@typescript-eslint/member-delimiter-style": "off", // Styling not forced upon the student
+    "@typescript-eslint/no-non-null-assertion": "off",
+    "@typescript-eslint/no-parameter-properties": [
+      "warn", {
+        "allows": [
+          "private", "protected", "public",
+          "private readonly", "protected readonly", "public readonly"
+        ]
+      }
+    ], // only disallow readonly without an access modifier
+    "@typescript-eslint/no-unused-vars": "off", // Covered by the tsc compiler (noUnusedLocals)
+    "@typescript-eslint/no-use-before-define": [
+      "error", {
+        "functions": false,
+        "typedefs": false
+      }
+    ], // Prevent bugs, not styling
+    "semi": "off", // Always disable base-rule
+    "@typescript-eslint/semi": "off" // Styling not forced upon student
+  }
+}

exercises/word-search/README.md

@@ -0,0 +1,63 @@
+# Word Search
+
+In word search puzzles you get a square of letters and have to find specific
+words in them.
+
+For example:
+
+```text
+jefblpepre
+camdcimgtc
+oivokprjsm
+pbwasqroua
+rixilelhrs
+wolcqlirpc
+screeaumgr
+alxhpburyi
+jalaycalmp
+clojurermt
+```
+
+There are several programming languages hidden in the above square.
+
+Words can be hidden in all kinds of directions: left-to-right, right-to-left,
+vertical and diagonal.
+
+Given a puzzle and a list of words return the location of the first and last
+letter of each word.
+## Setup
+
+Go through the setup instructions for TypeScript to install the necessary
+dependencies:
+
+[https://exercism.io/tracks/typescript/installation](https://exercism.io/tracks/typescript/installation)
+
+## Requirements
+
+Install assignment dependencies:
+
+```bash
+$ yarn install
+```
+
+## Making the test suite pass
+
+Execute the tests with:
+
+```bash
+$ yarn test
+```
+
+In the test suites all tests but the first have been skipped.
+
+Once you get a test passing, you can enable the next one by changing `xit` to
+`it`.
+
+## Source
+
+This is a classic toy problem, but we were reminded of it by seeing it in the Go Tour.
+
+## Submitting Incomplete Solutions
+
+It's possible to submit an incomplete solution so you can see how others have
+completed the exercise.

exercises/word-search/jest.config.js

@@ -0,0 +1,21 @@
+module.exports = {
+  verbose: true,
+  projects: [
+    '<rootDir>'
+  ],
+  testMatch: [
+    "**/__tests__/**/*.[jt]s?(x)",
+    "**/test/**/*.[jt]s?(x)",
+    "**/?(*.)+(spec|test).[jt]s?(x)"
+  ],
+  testPathIgnorePatterns: [
+    '/(?:production_)?node_modules/',
+    '.d.ts$',
+    '<rootDir>/test/fixtures',
+    '<rootDir>/test/helpers',
+    '__mocks__'
+  ],
+  transform: {
+    '^.+\\.[jt]sx?$': 'ts-jest',
+  },
+};

exercises/word-search/package.json

@@ -0,0 +1,29 @@
+{
+  "name": "@exercism/typescript",
+  "version": "1.0.0",
+  "description": "Exercism exercises in Typescript.",
+  "author": "",
+  "private": true,
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/exercism/typescript"
+  },
+  "devDependencies": {
+    "@types/jest": "^24.0.18",
+    "@types/node": "^12.7.12",
+    "@typescript-eslint/eslint-plugin": "^2.5.0",
+    "@typescript-eslint/parser": "^2.3.3",
+    "eslint": "^6.5.1",
+    "eslint-plugin-import": "^2.18.2",
+    "jest": "^24.9.0",
+    "ts-jest": "^24.1.0",
+    "typescript": "^3.6.4"
+  },
+  "scripts": {
+    "test": "yarn lint:types && jest --no-cache",
+    "lint": "yarn lint:types && yarn lint:ci",
+    "lint:types": "yarn tsc --noEmit -p .",
+    "lint:ci": "eslint . --ext .tsx,.ts"
+  },
+  "dependencies": {}
+}

exercises/word-search/tsconfig.json

@@ -0,0 +1,65 @@
+{
+  "compilerOptions": {
+    /* Basic Options */
+    "target": "es2017",                       /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */
+    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
+    "lib": ["esnext", "es2016", "es2017"],    /* Specify library files to be included in the compilation. */
+    // "allowJs": true,                       /* Allow javascript files to be compiled. */
+    // "checkJs": true,                       /* Report errors in .js files. */
+    // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
+    // "declaration": true,                   /* Generates corresponding '.d.ts' file. */
+    // "declarationMap": true,                /* Generates a sourcemap for each corresponding '.d.ts' file. */
+    "sourceMap": true,                        /* Generates corresponding '.map' file. */
+    // "outFile": "./",                       /* Concatenate and emit output to single file. */
+    "outDir": "./build",                      /* Redirect output structure to the directory. */
+    // "rootDirs": ["./"],                    /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
+    // "composite": true,                     /* Enable project compilation */
+    // "removeComments": true,                /* Do not emit comments to output. */
+    // "noEmit": true,                        /* Do not emit outputs. */
+    // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
+    // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
+    "isolatedModules": true,                  /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
+    "noEmitOnError": true,                    /* Do not emit outputs when compilation fails. */
+
+    /* Strict Type-Checking Options */
+    "strict": true,                           /* Enable all strict type-checking options. */
+    // "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */
+    // "strictNullChecks": true,              /* Enable strict null checks. */
+    // "strictFunctionTypes": true,           /* Enable strict checking of function types. */
+    // "strictBindCallApply": true,           /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
+    // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
+    // "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */
+    // "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */
+
+    /* Additional Checks */
+    // "noUnusedLocals": true,                /* Report errors on unused locals. */
+    "noUnusedParameters": true,               /* Report errors on unused parameters. */
+    // "noImplicitReturns": true,             /* Report error when not all code paths in function return a value. */
+    // "noFallthroughCasesInSwitch": true,    /* Report errors for fallthrough cases in switch statement. */
+
+    /* Module Resolution Options */
+    "moduleResolution": "node",               /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
+    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
+    // "paths": { "~src/*": ["./src/*"] },                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
+    // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
+    // "typeRoots": [],                       /* List of folders to include type definitions from. */
+    // "types": [],                           /* Type declaration files to be included in compilation. */
+    "allowSyntheticDefaultImports": true,     /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
+    "esModuleInterop": true                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
+    // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */
+
+    /* Source Map Options */
+    // "sourceRoot": "",                      /* Specify the location where debugger should locate TypeScript files instead of source locations. */
+    // "mapRoot": "",                         /* Specify the location where debugger should locate map files instead of generated locations. */
+    // "inlineSourceMap": true,               /* Emit a single file with source maps instead of having a separate file. */
+    // "inlineSources": true,                 /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
+
+    /* Experimental Options */
+    // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
+    // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */
+  },
+  "compileOnSave": true,
+  "exclude": [
+    "node_modules"
+  ]
+}

exercises/word-search/word-search.example.ts

@@ -0,0 +1,91 @@
+interface Result {
+  start: number[];
+  end: number[];
+}
+
+export default class WordSearch {
+  private grid: string[]
+  constructor(grid: string[]) {
+    this.grid = grid
+  }
+  private findCoordsWhereLetterMatch(currentLetter: string, board: string[]): number[][] {
+    return board.reduce((accumulatedCoordinates: number[][], row: string, rowNumber: number) => [...accumulatedCoordinates,
+      ...row.split('')
+        .reduce((matchingLetterIndecies: number[], letter: string, index: number) => letter === currentLetter ? [...matchingLetterIndecies, index] : matchingLetterIndecies, [])
+        .reduce((coordinates: number[][], col) => [...coordinates, [rowNumber, col]], [])
+    ],
+    [])
+  }
+
+  private getCoordsOfSurroundingLetters(initialCoord: number[], totalRows: number, totalColumns: number): number[][] {
+
+    const top: number[] = [initialCoord[0] - 1, initialCoord[1]]
+    const bottom: number[] = [initialCoord[0] + 1, initialCoord[1]]
+
+    const right: number[] = [initialCoord[0], initialCoord[1] + 1]
+    const left: number[] = [initialCoord[0], initialCoord[1] - 1]
+
+    const topRight: number[] = [initialCoord[0] + 1, initialCoord[1] + 1]
+    const topLeft: number[] = [initialCoord[0] + 1, initialCoord[1] - 1]
+
+    const bottomRight: number[] = [initialCoord[0] - 1, initialCoord[1] + 1]
+    const bottomLeft: number[] = [initialCoord[0] - 1, initialCoord[1] - 1]
+
+    return [top, bottom, right, left, topRight, topLeft, bottomRight, bottomLeft]
+      .filter((coordinates: number[]) =>
+        coordinates[0] <= (totalRows - 1) &&
+        coordinates[1] <= (totalColumns - 1) &&
+        coordinates[0] >= 0 &&
+        coordinates[1] >= 0)
+  }
+
+  private getValueFromCoordinate(board: string[], coordinates: number[]): string {
+    return board[coordinates[0]] && board[coordinates[0]].split('')[coordinates[1]]
+  }
+
+  private matchingValues(board: string[], coordinates: number[], letter: string): boolean {
+    return this.getValueFromCoordinate(board, coordinates) === letter
+  }
+
+  private getDirectionFunction(originCoords: number[], destinationCoords: number[]): (currentCoords: number[]) => number[] {
+    return (nextCoord: number[]): number[] => [nextCoord[0] + (destinationCoords[0] - originCoords[0]), nextCoord[1] + (destinationCoords[1] - originCoords[1])]
+  }
+
+
+  private getValidNeighbouringCoordinates(initial: number[], board: string[], letter: string): number[][] {
+    return this.getCoordsOfSurroundingLetters(initial, board.length, board[0].length)
+      .filter(neighbouringCoordinate => this.matchingValues(board, neighbouringCoordinate, letter))
+  }
+
+  private findOne(word: string, board: string[]): Result {
+    const allPossibleStartCoords: number[][] = this.findCoordsWhereLetterMatch(word[0], board)
+    const allPossibleCoordsForFirstTwoLetters: number[][][] = allPossibleStartCoords.reduce((accum: number[][][], initial) => {
+      return [...accum, ...this.getValidNeighbouringCoordinates(initial, board, word[1]).map(secondCoordinate => [initial, secondCoordinate])]
+    }, [])
+
+    const allPossiblePaths: number[][][] = allPossibleCoordsForFirstTwoLetters.map((coordsSoFar: number[][]) => {
+      const incrementFunction = this.getDirectionFunction(coordsSoFar[0], coordsSoFar[1])
+      return word.substr(2, word.length).split('').reduce((accum: number[][], _) => [...accum, incrementFunction(accum[accum.length - 1])], coordsSoFar)
+    })
+
+    const validPaths: number[][][] = allPossiblePaths.reduce((validPaths: number[][][], path: number[][]) =>
+      word.split('')
+        .map((letter, index) => this.matchingValues(board, path[index], letter))
+        .includes(false) ? validPaths : [...validPaths, path], [] as number[][][])
+
+
+    return validPaths.reduce((_: Result, path: number[][]) => ({
+      start: path[0].map(c => c + 1),
+      end: path[path.length - 1].map(c => c + 1)
+    }), {} as Result)
+  }
+
+  public find(words: string[]): { [word: string]: Result } | { [word: string]: undefined } {
+    return words.reduce((accum: { [word: string]: Result } | { [word: string]: undefined }, word) => {
+      const result = this.findOne(word, this.grid)
+      accum[word] = Object.keys(result).length == 0 ? undefined : result
+
+      return accum
+    }, {} as { [word: string]: Result } | { [word: string]: undefined })
+  }
+}