2 Examples of Javascript Sorting Algorithm Merge Sort (Merge Sort)_Basic Knowledge

/**
* Merge operation (merge), also called merge algorithm, refers to the operation of merging two sorted sequences into one sequence.
* The merge sort algorithm relies on merge operations.
*
* The process of merging operation is as follows:
*
* 1. Apply for space so that its size is the sum of two sorted sequences. This space is used to store the merged sequence
* 2. Set two pointers, the initial positions are the starting positions of the two sorted sequences
* 3. Compare the elements pointed to by the two pointers, select the relatively small element and put it into the merge space, and Move the pointer to the next position
* 4. Repeat step 3 until a pointer reaches the end of the sequence
* 5. Copy all remaining elements of the other sequence directly to the end of the merged sequence
*
*/

function mergeSort(items) {
if (items.length < 2) {
return items;
}

var middle = Math.floor(items.length / 2) ,
left = items.slice(0, middle),
right = items.slice(middle),
params = merge(mergeSort(left), mergeSort(right));

params.unshift(0, items.length);
items.splice.apply(items, params);

return items;

function merge(left, right) {
var result = [],
il = 0,
ir = 0;

while (il < left.length && ir < right.length) {
if ( left[il] < right[ir]) {
                               result.push(left[il]); >                                                           return result.concat(left.slice(il)) .concat(right.slice(ir)); = [2, 1, 3, 12, 5, 66, 23, 87, 15, 32];

mergeSort(arr);



Example 2:





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