常见排序算法

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不多说直接上代码，代码中实现了：快速排序、堆排序、直接插入排序、希尔排序
package com.scalahome;/** * Created by Administrator on 2016/8/14. */public class SortDemo {    public static void main(String[] args) {        int[] array = new int[]{2,24,4,53,2551,32,531,4,1,43,-24,2,53};        SortDemo sortDemo = new SortDemo();        sortDemo.printArray(array);//        sortDemo.quickSort(array);//        sortDemo.heapSort(array);//        sortDemo.insertSort(array);        sortDemo.shellSort(array);        sortDemo.printArray(array);    }    /**     * 希尔排序     *     * @param array     */    public void shellSort(int[] array) {        for(int gap = array.length / 2; gap > 0; gap = gap / 2) {            for(int offset = 0; offset < gap; offset++) {                insertSort(array, gap, offset);            }        }    }    public void insertSort(int[] array, int gap, int offset) {        for(int i = offset + gap; i < array.length; i += gap) {            int j = i - gap;            int newElement = array[i];            for(; j >= 0 && array[j] > newElement; j -= gap) {                array[j + gap] = array[j];            }            array[j + gap] = newElement;        }    }    /**     * 直接插入排序     *     * @param array     */    public void insertSort(int[] array) {        for(int i = 1; i < array.length; i++) {            int j = i - 1;            int newElement = array[i];            for(; j >= 0 && array[j] > newElement; j--) {                array[j + 1] = array[j];            }            array[j + 1] = newElement;        }    }    /**     * 堆排序     *     * @param array     */    public void heapSort(int[] array) {        for(int i = array.length - 1; i > 0; i--) {            maxHeap(array, i);            swap(array, 0, i);        }    }    public void maxHeap(int[] array, int lastPosition) {        for(int i = lastPosition / 2; i >= 0; i--) {            int j = i;            while (2 * j + 1 <= lastPosition) {                int firstChildIndex = 2 * j + 1;                int secondChildIndex = firstChildIndex + 1;                int bigger = firstChildIndex;                if(secondChildIndex < lastPosition && array[secondChildIndex] > array[firstChildIndex]) {                    bigger = secondChildIndex;                }                if(array[bigger] > array[j]) {                    swap(array, j, bigger);                    j = bigger;                } else {                    break;                }            }        }    }    /**     * 快速排序     *     * @param array     */    public void quickSort(int[] array) {        quickSort(array, 0, array.length - 1);    }    public void quickSort(int[] array, int start, int to) {        if(start >= to)            return;        int position = partitionSort(array, start, to);        quickSort(array, start, position);        quickSort(array, position + 1, to);    }    public int partitionSort(int[] array, int from, int to) {        int i = from;        int j = to;        int value = array[i];        int flag = 0;        while(j > i) {            if(flag == 0) {                if(array[j] < value) {                    swap(array, i, j);                    flag = (flag + 1) % 2;                } else {                    j--;                }            } else {                if(array[i] > value) {                    swap(array, i, j);                    flag = (flag + 1) % 2;                } else {                    i++;                }            }        }        return i;    }    public void swap(int[] array, int pos1, int pos2) {        array[pos1] = array[pos1] ^ array[pos2];        array[pos2] = array[pos1] ^ array[pos2];        array[pos1] = array[pos1] ^ array[pos2];    }    public void printArray(int[] array) {        StringBuilder buffer = new StringBuilder();        buffer.append('[');        for(int item : array) {            buffer.append(item);            buffer.append(',');        }        buffer.setLength(buffer.length() - 1);        buffer.append(']');        System.out.println(buffer.toString());    }}
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