在JavaScript中实现分而治之逻辑以实现QuickSort
我们需要编写一个JavaScript函数，该函数接受一个数字数组并使用快速排序算法对其进行排序。
快速排序
此算法基本上是分治法，我们在循环的每个遍历中选择一个枢轴，并将所有小于枢轴的元素置于其左侧，而将所有大于枢轴的元素置于其右侧（如果其升序排序相反）
示例
让我们为该函数编写代码-
const arr = [43, 3, 34, 34, 23, 232, 3434, 4, 23, 2, 54, 6, 54];
// Find a "pivot" element in the array to compare all other
// elements against and then shift elements before or after
// pivot depending on their values
const quickSort = (arr, left = 0, right = arr.length - 1) => {
let len = arr.length, index;
if(len > 1) {
index = partition(arr, left, right)
if(left < index - 1) {
quickSort(arr, left, index - 1)
}
if(index < right) {
quickSort(arr, index, right)
}
}
return arr
}
const partition = (arr, left, right) => {
let middle = Math.floor((right + left) / 2),
pivot = arr[middle],
i = left, // Start pointer at the first item in the
array
j = right // Start pointer at the last item in the array
while(i <= j) {
// Move left pointer to the right until the value at the
// left is greater than the pivot value
while(arr[i] < pivot) {
i++
}
// Move right pointer to the left until the value at the
// right is less than the pivot value
while(arr[j] > pivot) {
j--
}
// If the left pointer is less than or equal to the
// right pointer, then swap values
if(i <= j) {
[arr[i], arr[j]] = [arr[j], arr[i]] // ES6 destructuring swap
i++
j--
}
}
return i
}
console.log(quickSort(arr));输出结果
控制台中的输出-
[ 2, 3, 4, 6, 23, 23, 34, 34, 43, 54, 54, 232, 3434 ]