快速排序 Quick Sort

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自己寫的代碼，記錄一下。分別記錄了兩種partition的方法。

public class QuickSort {    public static void quickSort(int[] nums, int start, int end) {        if(start >= end) {            return;        }        int pivot = partition2(nums, start, end);        quickSort(nums, start, pivot - 1);        quickSort(nums, pivot + 1, end);    }    public static int partition(int[] nums, int start, int end) {        int pivot = start;        for(int i = start + 1; i <= end; i++) {            if(nums[i] <= nums[start]) {                pivot++;                int temp = nums[pivot];                nums[pivot] = nums[i];                nums[i] = temp;            }        }        int temp = nums[pivot];        nums[pivot] = nums[start];        nums[start] = temp;        return pivot;    }//    better partition method    public static int partition2(int[] nums, int start, int end) {        int pivot = start, i = start + 1, j = end;        while(i < j) {            while(i <= end && nums[i] <= nums[pivot]) {                i++;            }            while(nums[j] >nums[pivot]) {                j--;            }            if(i >= j) {                break;            }            int temp = nums[i];            nums[i] = nums[j];            nums[j] = temp;        }        i--;        int temp = nums[i];        nums[i] = nums[pivot];        nums[pivot] = temp;        return i;    }    public static void main(String[] args) {        int[] nums = new int[]{13, 6, 9, 1, 19, -21, 5};        quickSort(nums, 0, nums.length - 1);        System.out.println(nums);    }}

 

快速排序 Quick Sort