配列の基本アルゴリズメモ

配列の次元を指定された順序で並べ替え

const permute = str => {
  if (str.length === 1) {
    return [str]
  };
  let arr = str.split('');
  let result = [];
  for (let i = 0; i < arr.length; i++) {
    rArr = arr.filter(item => item !== arr[i]);
    let nArr = permute(rArr.join(''));
    result = result.concat(nArr.map(item => arr[i] + item));
  }
  return result;
}
console.log(permute('hello'));

数字のみが含まれた配列要素のクイックソート

const qSort = array => {
  if (array.length <= 1) return array
  let mi = Math.floor(array.length / 2)
  let m = array.splice(mi, 1)[0]
  let left = []
  let right = []
  for (let i = 0; i < array.length; i++) {
    array[i] < m ? left.push(array[i]) : right.push(array[i])
  }
  return [...qSort(left), m, ...qSort(right)]
}

console.log(qSort([0,-5,10,-8,8]));