31:T41f,{ let size = 40; const height = size + 10 + quicksortResults.swaps.length * size * 2; const canvas = DOM.canvas(width, height); var context = canvas.getContext("2d"); context.font = '40px monospace'; let current = [...quicksortResults.input]; let y = size; for (let step = 0; step <= quicksortResults.swaps.length; step++) { if (step != 0) { context.strokeStyle = "#ccc"; quicksortResults.swaps[step - 1].forEach(s => { context.moveTo(s[0] * size + 10, y - size * 2); context.lineTo(s[1] * size + 10, y - size); context.moveTo(s[1] * size + 10, y - size * 2); context.lineTo(s[0] * size + 10, y - size); [current[s[0]], current[s[1]]] = [current[s[1]], current[s[0]]]; }); } let p = current.forEach((o, i) => { if (quicksortResults.pivots[step] == i) { context.fillStyle = "red"; } else { context.fillStyle = "black"; } context.fillText(o, 40 * i, y); }); y += size * 2; } context.stroke(); return canvas; }32:[] 2f:{"title":"Programming Exercises","cells":[{"id":0,"value":"md`# Programming Exercises\n*with creative solutions*\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":34,"value":"md`## [Fizz buzz](https://en.wikipedia.org/wiki/Fizz_buzz)`","pinned":false,"hidden":false,"mode":"ojs"},{"id":51,"value":"viewof words = text({\n title: \"Words\",\n value: 'Fizz Buzz Baz',\n description:\n 'each space separated word is assigned to a prime number, starting at 3'\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":170,"value":"{\n const height = 400;\n let r = 1;\n let delta = 15;\n const context = DOM.context2d(width, height);\n\n let frame = 0,\n x = 0,\n y = 0;\n\n context.translate(width / 2, height / 2);\n context.textAlign = 'center';\n\n while (true) {\n frame += 1;\n\n let fb = fizzBuzzResults[frame];\n\n if (fb == null) {\n context.fillStyle = '#ccc';\n } else {\n let colorIndex = Object.keys(fb).reduce((im, io) => io * im, 1);\n\n context.fillStyle = `hsl(${(360 / fizzBuzzCombinations.length) *\n (fizzBuzzCombinations.indexOf(colorIndex) + 1)}, 100%, 50%)`;\n }\n\n let step = frame / 2;\n\n let angle = delta * step * (Math.PI / 180);\n\n x = r * step * Math.cos(angle);\n y = r * step * Math.sin(angle);\n\n context.save();\n context.translate(x, y);\n context.rotate(angle + Math.PI / 2);\n context.fillText(fb == null ? frame : Object.values(fb).join(''), 0, 0);\n context.restore();\n\n yield context.canvas;\n\n if (frame >= fizzBuzzResults.length - 1) break;\n }\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":369,"value":"md`**Solution (Divisible by: ${Object.keys(fizzBuzzModWords)\n .map(mod => {\n return `${mod} == ${fizzBuzzModWords[mod]}`;\n })\n .join(', ')})**: ${Object.entries(fizzBuzzResults)\n .slice(0, 30)\n .map(([k, v]) => (v == null ? k : Object.values(v).join(' ')))\n .join(', ')}...`","pinned":false,"hidden":false,"mode":"ojs"},{"id":395,"value":"fizzBuzzModWords = words.split(' ').reduce((o, w, i) => {\n if (w != '') o[primes[i + 1]] = w;\n return o;\n}, {})","pinned":false,"hidden":false,"mode":"ojs"},{"id":642,"value":"fizzBuzzCombinations = Object.keys(\n Object.values(fizzBuzzResults).reduce((m, o) => {\n if (o == null) return m;\n let k = Object.keys(o).reduce((im, io) => io * im, 1);\n if (k != 1) m[k] = k;\n return m;\n }, {})\n).map(Number)","pinned":false,"hidden":false,"mode":"ojs"},{"id":57,"value":"fizzBuzzResults = {\n return Array.from({ length: 1000 }, (_, i) => i + 1).reduce((m, o) => {\n let r = {};\n\n for (const mod in fizzBuzzModWords) {\n if (o % mod == 0) r[mod] = fizzBuzzModWords[mod];\n }\n\n if (Object.keys(r).length == 0) r = null;\n\n m[o] = r;\n\n return m;\n }, {});\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":924,"value":"md`## Recursion`","pinned":false,"hidden":false,"mode":"ojs"},{"id":928,"value":"{\n const height = 300;\n const context = DOM.context2d(width, height);\n\n let frame = 100,\n x = 0,\n y = 0;\n\n context.font = '10px monospace';\n\n let rect = (t, x, y, size) => {\n if (size <= 0) return;\n let angle = Math.cos(((t / 1000) * 180) / Math.PI);\n context.rotate(angle);\n\n context.strokeStyle = `hsl(${size * 100}, 100%, 50%)`;\n context.strokeRect(x, y, size, size);\n\n rect(t, x + 1, y - 1, size - 1);\n };\n\n let size = 100;\n\n while (true) {\n frame += .01;\n\n context.clearRect(0, 0, width, height);\n context.save();\n context.translate(size * 2, height / 2);\n rect(frame, 0, 0, size);\n context.restore();\n\n yield context.canvas;\n }\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":1832,"value":"md`## Fibonacci`","pinned":false,"hidden":false,"mode":"ojs"},{"id":1834,"value":"{\n const height = 210;\n let r = 1;\n let delta = 15;\n const context = DOM.context2d(width, height);\n\n let frame = 0,\n x = 0,\n y = 0;\n\n context.translate(0, 0);\n context.textAlign = 'left';\n\n let size = 20;\n context.font = `${size}px monospace`;\n\n let fibs = [[BigInt(1), BigInt(1)]];\n\n while (true) {\n let fib = fibs[fibs.length - 1];\n context.clearRect(0, 0, width, height);\n\n [fib[0], fib[1]] = [fib[1], fib[0] + fib[1]];\n\n frame += 1;\n\n let step = frame / 2;\n\n let angle = delta * step * (Math.PI / 180);\n\n fibs.forEach((f, i, a) => {\n context.fillStyle = `hsl(0,0%,${90 - i * a.length}%)`;\n context.fillText(`${f[0]} + ${f[1]} = ${f[0] + f[1]}`, 10, 20 + size * i);\n });\n\n fibs.push([...fib]);\n\n if (fibs.length > 10) fibs.shift();\n yield Promises.delay(100, context.canvas);\n }\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":1282,"value":"md`## Sorting`","pinned":false,"hidden":false,"mode":"ojs"},{"id":1287,"value":"viewof numbers = text({\n title: \"Numbers\",\n value: Math.round(Math.random() * 1e10)\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":1285,"value":"quicksortResults = {\n let data = {\n swaps: [],\n pivots: [],\n input: numbers.split('')\n };\n\n let partition = (a, start, end) => {\n let pivot = a[Math.floor((start + end) / 2)];\n data.pivots.push(pivot);\n\n let leftIndex = start - 1;\n let rightIndex = end + 1;\n\n let swaps = [];\n\n while (true) {\n do {\n leftIndex++;\n } while (a[leftIndex] < pivot);\n\n do {\n rightIndex--;\n } while (a[rightIndex] > pivot);\n\n if (leftIndex >= rightIndex) {\n if (swaps.length > 0) data.swaps.push(swaps);\n return rightIndex;\n }\n\n swaps.push([leftIndex, rightIndex]);\n [a[leftIndex], a[rightIndex]] = [a[rightIndex], a[leftIndex]];\n }\n };\n\n let quicksort = (a, start, end) => {\n if (start < end) {\n let p = partition(a, start, end);\n quicksort(a, start, p);\n quicksort(a, p + 1, end);\n }\n };\n\n data.output = [...data.input];\n quicksort(data.output, 0, data.input.length - 1);\n\n return data;\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":1366,"value":"$31","pinned":false,"hidden":false,"mode":"ojs"},{"id":4,"value":"md`## [Jewels and Stones](https://leetcode.com/problems/jewels-and-stones)`","pinned":false,"hidden":false,"mode":"ojs"},{"id":11,"value":"viewof jewels = text({\n title: \"Jewels\",\n value: '💍 💎'\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":12,"value":"viewof stones = text({\n title: \"Stones\",\n value: emoji.slice(0, 600).join(''),\n description: md`try emojis from https://observablehq.com/@jashkenas/every-emoji`\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":433,"value":"html`${shuffledStones.map(\n e =>\n `${e}`\n)}`","pinned":false,"hidden":false,"mode":"ojs"},{"id":574,"value":"cleanedStones = [...stones].filter(s => s.trim() != '')","pinned":false,"hidden":false,"mode":"ojs"},{"id":481,"value":"shuffledStones = {\n let s = [...cleanedStones];\n\n let r = [];\n let sl = s.length;\n for (let i = 0; i < sl; i++) {\n r.push(s.splice(Math.random() * s.length, 1)[0]);\n }\n\n return r;\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":440,"value":"jewelStones = cleanedStones.filter(s => jewels.includes(s))","pinned":false,"hidden":false,"mode":"ojs"},{"id":42,"value":"md`**Solution**: ${jewelStones.length}`","pinned":false,"hidden":false,"mode":"ojs"},{"id":166,"value":"md`## Helpers`","pinned":false,"hidden":false,"mode":"ojs"},{"id":80,"value":"primes = {\n // first 1k primes\n let p = Array.from({ length: 10000 }, (_, i) => i + 1);\n\n p = p.map(n => {\n if (n <= 1 || n == null) {\n return null;\n }\n\n for (let c = n - 1; c <= p.length; c += n) {\n p[c] = null;\n }\n\n return n;\n });\n\n return p.filter(Number);\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":8,"value":"import { checkbox, slider, text } from \"@jashkenas/inputs\"","pinned":false,"hidden":false,"mode":"ojs"},{"id":446,"value":"import { emoji } from '@jashkenas/every-emoji'","pinned":false,"hidden":false,"mode":"ojs"},{"id":1247,"value":"d3 = require('d3@6')","pinned":false,"hidden":false,"mode":"ojs"}],"files":"$W32","stdlib":"1","titling":"auto"}