在 JavaScript 中使用快速排序对文字数组进行排序
我们需要编写一个 JavaScript 函数,它使用快速排序算法对一个数字数组进行排序。
快速排序
此算法基本上是一个分治算法,我们在每个循环中选择一个基准,并将所有小于基准的元素放在其左侧,所有大于基准的元素放在其右侧(如果是升序排序,否则相反)
示例
代码如下 −
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
控制台中的输出 −
[ 2, 3, 4, 6, 23, 23, 34, 34, 43, 54, 54, 232, 3434 ]
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