如何在不使用排序方法（排序）或排序算法（冒泡排序、快速排序）的情况下对两个已排序的数组进行排序

Question

我在面试中被问到，我的回答与此类似，由于最终循环而导致错误。

const newSortArrays = (arr1, arr2) => {
     let output = [];
     while (arr1.length && arr2.length) {
        if (arr1[0] < arr2[0]) 
         output.push(arr1[0] < arr2[0] ? arr1.shift() : arr2.shift())
     }
     return [...output, ...arr1, ...arr2]
 }

Answer 1

您所说的“排序”两个本身已经排序的数组称为 merge。这就是你的做法：

function merge( left = [] , right = [] )  {
  const merged = new Array( left.length + right.length );

  let i = 0 ;
  let j = 0 ;
  let k = 0 ;

  // while both lists have items
  while ( i < left.length && j < right.length ) {
    const x = left[i];
    const y = right[j];

    if ( x <= y ) {
      merged[k++] = x;
      ++i;
    } else {
      merged[k++] = y;
      ++j;
    }

  }

  // if the left list still has items, take them
  while ( i < left.length ) {
    merged[k++] = left[ i++ ];
  }

  // if the right list still has items, take them
  while ( j < right.length ) {
    merged[k++] = right[ j++ ];
  }

  return merged;
}

Answer 2

一种（效率较低的）单循环变体：

  // While some list is not empty
  while ( i < left.length || j < right.length ) {
    if ( i < left.length && ( j >= right.length || left[i] < right[j] ) ) {
      merged[k++] = left[i];
      ++i;
    } else {
      merged[k++] = right[j];
      ++j;
    }
  }

如何在不使用排序方法（排序）或排序算法（冒泡排序、快速排序）的情况下对两个已排序的数组进行排序

How to sort two sorted arrays without using sort methods (sort) nor sort algorithms (bubble sort, quick sort)

javascript

algorithm

big-o