quick sort

Author: laileon

src/com/blankj/csutom/QuickSort.java

@@ -0,0 +1,46 @@
+package com.blankj.csutom;
+
+public class QuickSort {
+    public static void main(String[] args) {
+        int unsortedArray[] = new int[]{6, 5, 3, 1, 8, 7, 2, 4};
+        quickSort(unsortedArray);
+        System.out.println("After sort: ");
+        for (int item : unsortedArray) {
+            System.out.print(item + " ");
+        }
+    }
+
+    public static void quickSort2(int[] array, int l, int u) {
+        for (int item : array) {
+            System.out.print(item + " ");
+        }
+        System.out.println();
+        if (l >= u) return;
+        int pivot = array[l];
+        int left = l + 1;
+        int right = u;
+        while (left <= right) {
+            while (left <= right && array[left] < pivot) {
+                left++;
+            }
+            while (left <= right && array[right] >= pivot) {
+                right--;
+            }
+            if (left > right) break;
+            // swap array[left] with array[right] while left <= right
+            int temp = array[right];
+            array[right] = array[left];
+            array[left] = temp;
+        }
+        /* swap the smaller with pivot */
+        int temp = array[right];
+        array[right] = array[l];
+        array[l] = temp;
+        quickSort2(array, l, right - 1);
+        quickSort2(array, right + 1, u);
+    }
+
+    public static void quickSort(int[] array) {
+        quickSort2(array, 0, array.length - 1);
+    }
+}