java实现七种排序 （插入排序， 希尔排序， 插入排序， 快速排序， 简单选择排序， 堆排序， 归并排序）

package java_study.sort;import org.junit.Test;import java.util.Random;/** * Created by ethan on 2015/6/20. */public class Sort7 {    public int[] arr = init(10);    public int[] init(int len){        if (len==0) return null;        int[] arr = new int[len];        Random random = new Random();        for (int i=0; i<len; i++){           arr[i] =  random.nextInt(1000);        }        return arr;    }    // 插入排序    public int[] sort_insert(int[] arr) {        if (arr == null) return null;        for (int i = 1; i < arr.length; i++) {            int tmp = arr[i];            int j = i - 1;            for (; j >= 0 && tmp < arr[j]; j--) {                arr[j + 1] = arr[j];            }            arr[j + 1] = tmp;        }        return arr;    }    // 希尔排序    public int[] sort_shell(int[] arr) {        if (arr==null) return null;        int len = arr.length;        for (int i=len/2; i>0; i/=2){            for (int j=0; j<i; j++){                for (int m=j; m<len; m+=i){                    int tmp = arr[m];                    int n=m-i;                    for (; n>=j&&tmp<arr[n]; n-=i){                        arr[n+i] = arr[n];                    }                    arr[n+i]=tmp;                }            }        }        return arr;    }    // 冒泡排序    public int[] sort_bubble(int[] arr) {        if (arr == null) return null;        for (int i=0; i<arr.length-1; i++){            for (int j=0; j<arr.length-i-1; j++){                if (arr[j]>arr[j+1]){                    int tmp = arr[j];                    arr[j] = arr[j+1];                    arr[j+1] = tmp;                }            }        }        return arr;    }    // 快速排序    public int[] sort_fast(int[] arr) {        if (arr==null) return null;        sort_fast_implement(arr, 0, arr.length-1);        return arr;    }    public void sort_fast_implement(int[] arr, int start, int end){        if (start < end){            int index = partition(arr, start, end);            if (start<index){                sort_fast_implement(arr, start, index-1);            }            if (index<end){                sort_fast_implement(arr, index+1, end);            }        }    }    public int partition(int[] arr, int start, int end){        int tmp = arr[start];        while (start<end){            while (start<end&&tmp<arr[end]){                end--;            }            arr[start] = arr[end];            while (start<end&&tmp>arr[start]){                start++;            }            arr[end]=arr[start];        }        arr[start]=tmp;        return start;    }    // 选择排序    public int[] sort_choose(int[] arr) {        if (arr == null) return null;        for (int i=1; i<arr.length; i++){            int min_index = i-1;            for (int j=i; j<arr.length; j++){                if (arr[min_index]>arr[j]){                    min_index=j;                }            }            if (min_index!=i-1){                int tmp = arr[min_index];                arr[min_index] = arr[i-1];                arr[i-1] = tmp;            }        }        return arr;    }    // 堆排序 ==> 小根堆逆序， 大根堆顺序    public int[] sort_heap(int[] arr) {        if (arr==null) return null;        build_heap(arr);        for (int i=arr.length; i>0; i--){            int tmp = arr[0];            arr[0] = arr[i-1];            arr[i-1] = tmp;            heap_adjust(arr, 0, i-1);        }        return arr;    }    //建堆    public void build_heap(int[] arr){        if (arr==null) return;        if (arr.length==1) return;        int last = arr.length/2 - 1;        for (int i=last; i>=0 ;i--){            heap_adjust(arr, i, arr.length);        }    }    //adjust    public void heap_adjust(int[] arr, int index, int len){        if (index<0) return;        if (index>=len) return;        int left = index*2+1;        if (left>=len) return;        int right = index*2+2;        int max_index = left;        if (right<len && arr[right]>arr[ max_index]){             max_index = right;        }        if (arr[ max_index] > arr[index]){            int tmp = arr[ max_index];            arr[ max_index] = arr[index];            arr[index] = tmp;            heap_adjust(arr,  max_index, len);        }    }    // 归并排序    public int[] sort_merge(int[] arr) {        int[] tmp = new int[arr.length];        sort_merge_implement(arr, 0, arr.length-1, tmp);        return arr;    }    //    public void sort_merge_implement(int[] arr, int start, int end, int[] tmp){        if (start<end){            int mid = (start+end)/2;            sort_merge_implement(arr, start, mid, tmp);            sort_merge_implement(arr, mid+1, end, tmp);            merge_two_sorted_array(arr, start, mid, end, tmp);        }    }    // merge 两个有序的数组    public void merge_two_sorted_array(int[] arr, int start, int mid, int end, int[] tmp){        int start1 = start;        int end1 = mid;        int start2= mid+1;        int end2 = end;        int index = start;        while(start1<=end1 && start2<=end2){            if (arr[start1]<arr[start2]){                tmp[index++] = arr[start1++];            }else{                tmp[index++] = arr[start2++];            }        }        while(start1<=end1){            tmp[index++] = arr[start1++];        }        while (start2<=end2){            tmp[index++] = arr[start2++];        }        for (int i=start; i<=end; i++){            arr[i] = tmp[i];        }    }    // test    @Test    public void test_sort_insert() {        System.out.println("insert sort...........");        print_array(arr);        print_array(sort_insert(arr));    }    @Test    public void test_sort_shell() {        System.out.println("shell sort...........");        print_array(arr);        print_array(sort_shell(arr));    }    @Test    public void test_sort_bubble() {        System.out.println("bubble sort...........");        print_array(arr);        print_array(sort_bubble(arr));    }    @Test    public void test_sort_fast() {        System.out.println("fast sort...........");        print_array(arr);        print_array(sort_fast(arr));    }    @Test    public void test_sort_choose() {        System.out.println("choose sort...........");        print_array(arr);        print_array(sort_choose(arr));    }    @Test    public void test_sort_heap() {        System.out.println("heap sort...........");        print_array(arr);        print_array(sort_heap(arr));    }    @Test    public void test_sort_merge() {        System.out.println("merge sort...........");        print_array(arr);        print_array(sort_merge(arr));    }    public void print_array(int[] arr) {        if (arr == null) return;        for (int i = 0; i < arr.length; i++) {            System.out.print(arr[i] + " ");        }        System.out.println();    }}