Begin the euler project

.prettierrc

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+{
+	"semi": true,
+	"trailingComma": "none",
+	"singleQuote": true,
+	"printWidth": 100,
+	"tabWidth": 4,
+	"bracketSpacing": true,
+	"arrowParens": "avoid"
+}

euler/.gitignore

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+node_modules
+.yarn/cache
+.yarn/install-state.gz
+build

euler/.yarnrc.yml

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+yarnPath: .yarn/releases/yarn-3.1.0.cjs
+nodeLinker: node-modules

euler/_pythonarchive/1 - Multiples of 3 or 5.py

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+below = 1000
+multiplesOf = [3,5]
+toAdd = []
+
+for i in range(1, below):
+	for num in multiplesOf:
+		if i % num == 0:
+			toAdd.append(i)
+
+toAdd = list(dict.fromkeys(toAdd))
+total = 0
+
+for i in toAdd:
+	total += i
+
+print(total)

euler/_pythonarchive/2 - Even Fibonacci numbers.py

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+sequence = [1, 2]
+
+while sequence[len(sequence) - 1] < 4000000:
+	sequence.append(sequence[len(sequence) - 1] + sequence[len(sequence) - 2])
+sequence.pop()
+
+total = 0
+
+for i in sequence:
+	if i % 2 == 0:
+		total += i
+
+print(total)

euler/_pythonarchive/3 - Largest prime factor.py

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+n = 600851475143 
+i = 2
+
+while i * i <= n:
+	if n % i:
+		i += 1
+	else:
+		n //= i
+
+print(n)

euler/gulpfile.js

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+const gulp = require('gulp');
+const typescript = require('gulp-typescript');
+const uglify = require('gulp-uglify');
+const rename = require('gulp-rename');
+
+gulp.task('build', () => {
+    const tsc = typescript.createProject('tsconfig.json');
+
+    return gulp
+        .src('src/**/*.ts')
+        .pipe(tsc())
+        .pipe(uglify({ mangle: { toplevel: true } }))
+        .pipe(
+            rename(path => {
+                if (path.basename === 'utils') return;
+                path.basename = path.basename.substr(0, 1);
+            })
+        )
+        .pipe(gulp.dest('build'));
+});

euler/package.json

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+{
+    "name": "project-euler",
+    "packageManager": "yarn@3.1.0",
+    "scripts": {
+        "build": "gulp build",
+        "start": "node run"
+    },
+    "devDependencies": {
+        "@types/node": "^16.11.6",
+        "chalk": "^4.1.2",
+        "gulp": "^4.0.2",
+        "gulp-cli": "^2.3.0",
+        "gulp-rename": "^2.0.0",
+        "gulp-typescript": "^6.0.0-alpha.1",
+        "gulp-uglify": "^3.0.2",
+        "typescript": "^4.4.4"
+    }
+}

euler/run.js

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+const fs = require('fs');
+const chalk = require('chalk');
+const { spawnSync } = require('child_process');
+
+const run = (file, puzzleName) => {
+    // Calculate the length of the divider for the puzzle
+    let divider = '--';
+
+    for (let j = 0; j < puzzleName.length; j++) {
+        divider += '-';
+    }
+
+    // Log output
+    console.log(divider);
+    console.log(chalk.bold(chalk.greenBright(puzzleName)));
+    console.log(divider);
+
+    spawnSync('node', [`build/${file}`], { shell: true, stdio: 'inherit' });
+};
+
+// Get files
+const tsFiles = fs
+    .readdirSync('src')
+    .filter(f => f.endsWith('.ts'))
+    .filter(f => f !== 'utils.ts');
+const jsFiles = fs
+    .readdirSync('build')
+    .filter(f => f.endsWith('.js'))
+    .filter(f => f !== 'utils.js');
+
+try {
+    // Extract the puzzle number
+    const puzzleNumber = process.argv[2];
+    if (isNaN(puzzleNumber)) throw Error();
+
+    // Find the associated puzzle
+    const tsFile = tsFiles.filter(f => f.startsWith(puzzleNumber))[0];
+    const puzzleName = tsFile.split('.ts')[0];
+
+    run(`${puzzleNumber}.js`, puzzleName);
+} catch (error) {
+    for (let i = 0; i < jsFiles.length; i++) {
+        const file = jsFiles[i];
+        const tsFile = tsFiles[i];
+        const puzzleName = tsFile.split('.ts')[0];
+
+        run(file, puzzleName);
+        console.log();
+    }
+}

euler/src/1 - Multiples of 3 or 5.ts

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+import { calcSum } from './utils';
+
+const below = 1000;
+const multiplesOf = [3, 5];
+const toAdd: Set<number> = new Set();
+
+// Find all of the multiples of 3 and 5 below 1000
+for (let i = 1; i < below; i++) {
+    multiplesOf.forEach(num => (i % num == 0 ? toAdd.add(i) : null));
+}
+
+console.log(calcSum(Array.from(toAdd)));

euler/src/2 - Even Fibonacci Numbers.ts

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+import { calcSum } from './utils';
+
+const sequence = [1, 2];
+const max = 4000000;
+
+// Keep making new nujm
+while (sequence[sequence.length - 1] < max) {
+    const newValue = sequence[sequence.length - 1] + sequence[sequence.length - 2];
+
+    sequence.push(newValue);
+}
+
+// Filter out the even numbers and find the sum
+const even = sequence.filter(n => n % 2 === 0);
+console.log(calcSum(even));

euler/src/3 - Largest Prime Factor.ts

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+let number = 600851475143;
+let i = 2;
+
+while (i * i <= number) {
+    if (number % i) i += 1;
+    else number = Math.floor(number / i);
+}
+
+console.log(number);

euler/src/4 - Largest Palindrome Number.ts

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+const biggest = 999;
+const smallest = 100;
+
+// Work out all of the products of 3 digit numbers
+const products: number[] = [];
+
+for (let i = smallest; i < biggest + 1; i++) {
+    for (let j = smallest; j < biggest + 1; j++) {
+        products.push(i * j);
+    }
+}
+
+// Filter for palindromic numbers
+const palindromic = products.filter(
+    x => x.toString() === x.toString().split('').reverse().join('')
+);
+
+// Find the biggest palindrome number
+const sorted = palindromic.sort((a, b) => b - a);
+const largest = sorted[0];
+
+console.log(largest);

euler/src/utils.ts

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+/**
+ * Calculates the sum of an array of numbers.
+ */
+export const calcSum = (numbers: number[]) => numbers.reduce((a, b) => a + b);

euler/tsconfig.json

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+{
+    "compilerOptions": {
+        "target": "es5",
+        "module": "commonjs",
+        "outDir": "build"
+    },
+    "include": ["src/**/*.ts"],
+    "exclude": ["node_modules"]
+}