排序算法-----基数排序

基数排序是按照低位先排序，然后收集；在按照高位排序，然后在收集；依次类推，直到最高位。有时候有些属性是有优先级顺序的，先按低优先级排序，在按高优先级排序。最后的次序就是高优先级高的在前，高优先级相同的低优先级高的在前。
时间复杂度：O（n+m）
空间复杂度：O（n+m）
稳定性：稳定

package 排序算法;

import shixianClass.ArrayLoopQueue;

import java.util.Arrays;
import java.util.Random;

public class RadixSort {
    public static void main(String[] args) {
        int []arr=new int[20];
        Random random=new Random();
        for (int i=0;i<arr.length;i++){
            arr[i]=random.nextInt(50);
        }
        radixSort(arr);
        System.out.println(Arrays.toString(arr));
    }

    public static void radixSort(int[] arr) {
        //1.找到最大值
        int max=arr[0];
        for (int i=1;i<arr.length;i++){
            if(arr[i]>max){
                max=arr[i];
            }
        }
        //2.计算位数
        int radix=(max+"").length();
        //3.创建桶
        ArrayLoopQueue<Integer> [] backets=new ArrayLoopQueue[10];
        for (int i=0;i<backets.length;i++){
            backets[i]=new ArrayLoopQueue<>();
        }

        for (int r=1;r<=radix;r++){
            for (int i=0;i<arr.length;i++){
                backets[getIndex(arr[i],r)].offer(arr[i]);
            }
           int index=0;
            for (int i=0;i<backets.length;i++){
                while (!backets[i].isEmpty()){
                    arr[index++]=backets[i].poll();
                }
            }
        }
    }

    private static int getIndex(int num, int r) {
        int ret=0;
        ret=num%10;
        for (int i=1;i<=r;i++){
            ret=num%10;
            num/=10;
        }
        return ret;
    }
}

执行结果

[0, 3, 9, 12, 15, 15, 25, 26, 30, 30, 32, 33, 34, 38, 43, 44, 44, 46, 46, 47]

测试

package 排序算法;

import java.util.Arrays;
import java.util.Random;

public class TestSort {
    /*
    数据分布情况
    1.完全随机
    2.大致有序
    3.方差小
     */
    public static int[] getTotalRandom(){
        Random random=new Random();
        int [] arr=new int[40000];
        for (int i=0;i<arr.length;i++){
            arr[i]=random.nextInt(10000);
        }
        return arr;
    }

    public static void main(String[] args) {
        int [] arr1=getTotalRandom();
        int [] arr2= Arrays.copyOf(arr1, arr1.length);
        int [] arr3= Arrays.copyOf(arr1, arr1.length);
        int [] arr4= Arrays.copyOf(arr1, arr1.length);
        int [] arr5= Arrays.copyOf(arr1, arr1.length);
        int [] arr6= Arrays.copyOf(arr1, arr1.length);
        int [] arr7= Arrays.copyOf(arr1, arr1.length);
        int [] arr8= Arrays.copyOf(arr1, arr1.length);
        int [] arr9= Arrays.copyOf(arr1, arr1.length);
        int [] arr10= Arrays.copyOf(arr1, arr1.length);
        int [] arr11= Arrays.copyOf(arr1, arr1.length);
        int [] arr12= Arrays.copyOf(arr1, arr1.length);
       /* testSelectionSort(arr1);
        testBubbleSort(arr2);
        testInsertSort(arr3);
        testShellSort(arr4);
        testMergSort(arr5);
        testHeapSort(arr6);*/
        testQuickSort01(arr7);
        testQuickSort02(arr8);
        testQuickSort09(arr9);
        testCounting(arr10);
        testBucketSort(arr11);
        testRadixSort(arr12);


    }

    private static void testRadixSort(int[] arr12) {
        long startTime=System.currentTimeMillis();
        RadixSort.radixSort(arr12);
        long endTime=System.currentTimeMillis();
        System.out.println("基数排序"+(endTime-startTime));
    }

    private static void testBucketSort(int[] arr11) {
        long startTime=System.currentTimeMillis();
        BucketSort. buckrtSort(arr11);
        long endTime=System.currentTimeMillis();
        System.out.println("桶排序"+(endTime-startTime));
    }

    private static void testCounting(int[] arr10) {
        long startTime=System.currentTimeMillis();
        CountingSort.countingSort(arr10);
        long endTime=System.currentTimeMillis();
        System.out.println("计数排序"+(endTime-startTime));

    }

    private static void testQuickSort09(int[] arr9) {
        long startTime=System.currentTimeMillis();
        QuickSort03.quickSort03(arr9,0,arr9.length-1);
        long endTime=System.currentTimeMillis();
        System.out.println("三路快排"+(endTime-startTime));
    }

    private static void testQuickSort02(int[] arr8) {
        long startTime=System.currentTimeMillis();
        QuickSort02.quickSort02(arr8,0,arr8.length-1);
        long endTime=System.currentTimeMillis();
        System.out.println("双路快排"+(endTime-startTime));

    }

    private static void testQuickSort01(int[] arr7) {
        long startTime=System.currentTimeMillis();
        QuickSort01.quickSort(arr7,0,arr7.length-1);
        long endTime=System.currentTimeMillis();
        System.out.println("单路快排"+(endTime-startTime));
    }

    private static void testHeapSort(int[] arr6) {
            long startTime=System.currentTimeMillis();
            HeapSort.heapSort(arr6);
            long endTime=System.currentTimeMillis();
            System.out.println("堆排序"+(endTime-startTime));
    }

    private static void testInsertSort(int[] arr3) {
        long startTime=System.currentTimeMillis();
        BubbleSort.bubbleSort(arr3);
        long endTime=System.currentTimeMillis();
        System.out.println("冒泡排序"+(endTime-startTime));
    }

    private static void testBubbleSort(int[] arr2) {
        long startTime=System.currentTimeMillis();
        insertionSort.lnsertionSortUpper(arr2);
        long endTime=System.currentTimeMillis();
        System.out.println("插入排序"+(endTime-startTime));
    }

    private static void testSelectionSort(int[] arr) {
        long startTime=System.currentTimeMillis();
        SelectionSort.selectionSort(arr);
        long endTime=System.currentTimeMillis();
        System.out.println("选择排序"+(endTime-startTime));
    }
    private static void testShellSort(int[] arr) {
        long startTime=System.currentTimeMillis();
        ShellSort.shellSort(arr);
        long endTime=System.currentTimeMillis();
        System.out.println("希尔排序"+(endTime-startTime));
    }
    private static void testMergSort(int[] arr) {
        long startTime=System.currentTimeMillis();
        MergSort.mergSort(arr,0,arr.length-1);
        long endTime=System.currentTimeMillis();
        System.out.println("归并排序"+(endTime-startTime));
    }

}

执行结果

选择排序2084
插入排序142
冒泡排序2855
希尔排序8
归并排序279
堆排序2660
单路快排5
双路快排7
三路快排9
计数排序2
桶排序942
基数排序20