Java 实现的快速排序

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一、快排介绍

不懂基本原理的可以看一下百度百科-快速排序。有两种实现方式，一种是使用partition函数；另外就是普通的

二、Java 代码

//使用partition方法public void quickSort(int[] nums, int low, int high){if (nums==null || nums.length==0 || low > high) {return ;}int idx = partition(nums, low, high, low);quickSort(nums, low, idx-1);quickSort(nums, idx+1, high);}public int partition(int[] nums, int low, int high, int pivotIdx){int pivot = nums[pivotIdx];swap(nums, pivotIdx, high);int startIdx = low;for (int i = low; i < high; i++) {if (nums[i]<pivot) {swap(nums, i, startIdx);startIdx++;}}swap(nums, startIdx, high);return startIdx;}private void swap(int[] nums, int a, int b){int tmp = nums[a];nums[a] = nums[b];nums[b] = tmp;}//一般快排public void quickSort2(int[] arr, int left, int right) {          if (left >= right) {              return;          }          int low = left;          int high = right;          int key = arr[low];          while (low < high) {              while (low < high && arr[high] >= key)                  high--;            if (low<high) {            arr[low++] = arr[high];  }            while (low < high && arr[low] <= key)                  low++;              if (low<high) {            arr[high--] = arr[low];}        }          arr[low] = key;          quickSort(arr, left, low - 1);          quickSort(arr, low + 1, right);      }

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