matthieuprat · June 13, 2018 06:58
diff --git a/array-shuffle.js b/array-shuffle.js
 const shuffle = arr =>
  arr.reduce((arr, elt) => {
    arr.splice(~~(Math.random() * (arr.length + 1)), 0, elt)
    return arr
  }, [])
diff --git a/array-shuffle:check-un-biased.js b/array-shuffle:check-un-biased.js
 const shuffle = arr =>
  arr.reduce((arr, elt) => {
    arr.splice(~~(Math.random() * (arr.length + 1)), 0, elt)
    return arr
  }, [])

 /**
 * Calls the supplied function a number of times and computes the distribution
 * of return values.
 */
 function distrib(fn, iterations) {
  iterations = ~~iterations || 1 << 20
  const distrib = new Map()

  while (iterations--) {
    let r = fn().toString()
    distrib.set(r, 1 + distrib.get(r) || 0)
  }

  // Normalize distrib.
  const mag = Math.sqrt([...distrib.values()].reduce((mag, c) => mag + c * c, 0))
  distrib.forEach((val, key) => distrib.set(key, val / mag))

  return distrib
 }

 distrib(() => shuffle([1, 2, 3])) // Check that `shuffle` is un-biased.
diff --git a/array-shuffle:golf.js b/array-shuffle:golf.js
 const shuffle = a => a.reduce((a, e) => (a.splice(Math.random() * (a.length + 1), 0, e), a), [])
	const shuffle = arr =>
	arr.reduce((arr, elt) => {
	arr.splice(~~(Math.random() * (arr.length + 1)), 0, elt)
	return arr
	}, [])
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