2019-3-29

const checkboxes = Array.from(document.querySelectorAll(‘input[type=”checkbox”]’));
checkboxes.forEach((checkbox) => {checkbox.addEventListener(‘click’, a)});
function a(e) {
if (e.shiftKey && this.checked) {

// event 不同的话 e 的属性也是不同的哦

//选择排序  selection sorting
function selectionSort(arr) {
  for (let i=0; i<arr.length; i++) {
    let indexofMin = i;
    for (let j=i+1; j<arr.length; j++) {
      if (arr[j] < arr[indexofMin]) {
        indexofMin = j;
      }
    }
    if (i !== indexofMin) {
      [arr[i], arr[indexofMin]] = [arr[indexofMin], arr[i]];
    } 
  }
  return arr;
}

// 并归排序
function mergeSort(arr) {
  if (arr.length === 1) {
    return arr;
  }
  const center = Math.floor(arr.length / 2);
  const left = arr.slice(0, center);
  const right = arr.slice(center);
  return merge(mergeSort(left), mergeSort(right));
}
function merge(left, right) {
  const results = [];
  while (left.length && right.length) {
    if (left[0] < right[0]) {
      results.push(left.shift());
    } else {
      results.push(right.shift());
    }
  }
  return [...results, ...left, ...right];
}