BFE.devAI解答 - JavaScript 代码题
41. 手写Merge Sort

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

时间复杂度为O(nlogn)，空间复杂度为O(n)，是稳定排序。