Java8种排序算法学习

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冒泡排序

public class test {  
    public static void main(String[] args) {  
        // TODO Auto-generated method stub  
        int numbers[] = { 6, 2, 4, 1, 5, 9 };  
        BubbleSort(numbers);  
    }  

    public static void BubbleSort(int [] numbers){  
        for (int i = 0; i < numbers.length - 1; i++) { // 最多做n-1趟排序  
            for (int j = 0; j < numbers.length - i - 1; j++) { // 对当前无序区间numbers[0......n-i-1]进行排序(j的范围很关键，这个范围是在逐步缩小的)  
                if (numbers[j] > numbers[j + 1]) { // 把大的值交换到后面  
                    int temp = numbers[j];  
                    numbers[j] = numbers[j + 1];  
                    numbers[j + 1] = temp;  
                }  
            }  
        }  
        System.out.print("最终排序结果："+" ");  
        for (int i = 0; i < numbers.length; i++) {  
            System.out.print(numbers[i]+" ");  
        }  
    }  
}  

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选择排序

public class test {  
    public static void main(String[] numbersrgs) {  
        int [] numbers={6,2,4,1,9,8,3};  
        SelectionSort(numbers);  
        System.out.print("选择排序结果为：  ");  
        for (int i : numbers)  
            System.out.print(i + " ");  
    }  

    private static void SelectionSort(int [] numbers){  
         int n = numbers.length;  
            for (int i = 0; i < n; i++) {  
                int k = i;  
                // 找出最小值的小标，找到之后赋值给K，numbers[k]即为最小值  
                for (int j = i + 1; j < n; j++) {  
                    if (numbers[j] < numbers[k]) {  
                        k = j;  
                    }  
                }  
                // 将最小值放到排序序列末尾  
                if (k > i) {  
                    int tmp = numbers[i];  
                    numbers[i] = numbers[k];  
                    numbers[k] = tmp;  
                }  
            }     
    }  
}  

---

插入排序

public class test2{  
    public static void main(String[] args) {      
        int [] nums={8,6,10,5,7,9,11};  
        sortCore(nums);  
    }  

    private static void sortCore(int[] array) {  
        int arraySize = array.length;  

        for (int i = 1; i < arraySize; i++) {  
            int j = i;  

            int waitInsert = array[i];  
            while(j > 0 && waitInsert < array[j - 1]) {  
                array[j] = array[j - 1];  
                j--;  
            }  
            array[j] = waitInsert;  
        }  

        System.out.print("最终的排序为：");  
        for(int i:array)  
            System.out.print(i+" ");  
    }  
}  

---

归并排序

public class test_cow {  
    public static void main(String[] args) {  
        int [] numbers={6,2,4,1,9,8,3,15};  
        sort(numbers);  
        System.out.print("归并排序的结果为：");  
        for(int i:numbers){  
            System.out.print(i+" ");  
        }  

    }  

    public static void sort(int[] data) {  
        int[] temp = new int[data.length];  
        mergeSort(data, temp, 0, data.length - 1);  
    }  

    private static void mergeSort(int[] data, int[] temp, int left, int right) {  
        int mid = (left + right) / 2;  
        if (left == right)  
            return;  
        mergeSort(data, temp, left, mid);  
        mergeSort(data, temp, mid + 1, right);  

        for (int i = left; i <= right; i++) {  
            temp[i] = data[i];  
        }  
        int i1 = left;  
        int i2 = mid + 1;  
        for (int cur = left; cur <= right; cur++) {  
            if (i1 == mid + 1)  
                data[cur] = temp[i2++];  
            else if (i2 > right)  
                data[cur] = temp[i1++];  
            else if (temp[i1] < temp[i2])  
                data[cur] = temp[i1++];  
            else  
                data[cur] = temp[i2++];  
        }  
    }  
}  

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堆排序

public class test_sort {  

    public static void main(String[] args) {  
        int[] nums = new int[] { 5, 3, 6, 2, 1, 9, 4, 8, 7 };  
        print(nums);  
        heapSort(nums);  
        System.out.println("排序后的数组：");  
        print(nums);  
    }  

    public static void swap(int[] data, int i, int j) {  
        if (i == j) {  
            return;  
        }  
        data[i] = data[i] + data[j];  
        data[j] = data[i] - data[j];  
        data[i] = data[i] - data[j];  
    }  

    public static void heapSort(int[] data) {  
        for (int i = 0; i < data.length; i++) {  
            createMaxdHeap(data, data.length - 1 - i);  
            swap(data, 0, data.length - 1 - i);  
            print(data);  
        }  
    }  

    public static void createMaxdHeap(int[] data, int lastIndex) {  
        for (int i = (lastIndex - 1) / 2; i >= 0; i--) {  
            // 保存当前正在判断的节点  
            int k = i;  
            // 若当前节点的子节点存在  
            while (2 * k + 1 <= lastIndex) {  
                // biggerIndex总是记录较大节点的值,先赋值为当前判断节点的左子节点  
                int biggerIndex = 2 * k + 1;  
                if (biggerIndex < lastIndex) {  
                    // 若右子节点存在，否则此时biggerIndex应该等于 lastIndex  
                    if (data[biggerIndex] < data[biggerIndex + 1]) {  
                        // 若右子节点值比左子节点值大，则biggerIndex记录的是右子节点的值  
                        biggerIndex++;  
                    }  
                }  
                if (data[k] < data[biggerIndex]) {  
                    // 若当前节点值比子节点最大值小，则交换2者得值，交换后将biggerIndex值赋值给k  
                    swap(data, k, biggerIndex);  
                    k = biggerIndex;  
                } else {  
                    break;  
                }  
            }  
        }  
    }  

    public static void print(int[] data) {  
        for (int i = 0; i < data.length; i++) {  
            System.out.print(data[i] + " ");  
        }  
        System.out.println();  
    }  
}  

---

希尔排序

public class test_sort {  
    public static int count = 0;  
    public static void main(String[] args) {  

        int[] nums = new int[] { 5, 3, 6, 2, 1, 9, 4, 8, 7 };  
        print(nums);  
        shellSort(nums);  
        System.out.println("希尔排序最终结果为：");  
        print(nums);  
    }  

    public static void shellSort(int[] data) {  
        // 计算出最大的h值  
        int h = 1;  
        while (h <= data.length / 3) {  
            h = h * 3 + 1;  
        }  
        while (h > 0) {  
            for (int i = h; i < data.length; i += h) {  
                if (data[i] < data[i - h]) {  
                    int tmp = data[i];  
                    int j = i - h;  
                    while (j >= 0 && data[j] > tmp) {  
                        data[j + h] = data[j];  
                        j -= h;  
                    }  
                    data[j + h] = tmp;  
                    print(data);  
                }  
            }  
            // 计算出下一个h值  
            h = (h - 1) / 3;  
        }  
    }  

    public static void print(int[] data) {  
        for (int i = 0; i < data.length; i++) {  
            System.out.print(data[i] + "	");  
        }  
        System.out.println();  
    }  

}  

---

基数排序

import java.util.Arrays;  

public class test_sort {  

    public static void main(String[] args) {  
        int[] nums = new int[] { 102, 52, 21, 12, 23 ,1,50,63,5,98};  
        print(nums);  
        radixSort(nums, 10, 4);  
        System.out.println("基数排序后的数组：");  
        print(nums);  
    }  

    public static void radixSort(int[] data, int radix, int d) {  
        // 缓存数组  
        int[] tmp = new int[data.length];  
        // buckets用于记录待排序元素的信息  
        // buckets数组定义了max-min个桶  
        int[] buckets = new int[radix];  

        for (int i = 0, rate = 1; i < d; i++) {  

            // 重置count数组，开始统计下一个关键字  
            Arrays.fill(buckets, 0);  
            // 将data中的元素完全复制到tmp数组中  
            System.arraycopy(data, 0, tmp, 0, data.length);  

            // 计算每个待排序数据的子关键字  
            for (int j = 0; j < data.length; j++) {  
                int subKey = (tmp[j] / rate) % radix;  
                buckets[subKey]++;  
            }  

            for (int j = 1; j < radix; j++) {  
                buckets[j] = buckets[j] + buckets[j - 1];  
            }  

            // 按子关键字对指定的数据进行排序  
            for (int m = data.length - 1; m >= 0; m--) {  
                int subKey = (tmp[m] / rate) % radix;  
                data[--buckets[subKey]] = tmp[m];  
            }  
            rate *= radix;  
        }  

    }  

    public static void print(int[] data) {  
        for (int i = 0; i < data.length; i++) {  
            System.out.print(data[i] + "	");  
        }  
        System.out.println();  
    }  

}  

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快速排序

/* 基于分治的思想，是冒泡排序的改进型 
 * 快速排序和归并排序都使用分治法来设计算法，区别在于归并排序把数组分为两个基本等长的子数组， 
 * 分别排好序之后还要进行归并(Merge)操作，而快速排序拆分子数组的时候显得更有艺术，取一个基准元素， 
 * 拆分之后基准元素左边的元素都比基准元素小，右边的元素都不小于基准元素，这样只需要分别对两个子数组排序即可， 
 * 不再像归并排序一样需要归并操作。 
 * */  
public class test_cow{  

    public static void main(String []args){  
       int[] nums = {6,2,4,1,9,8,3,15};  
       int start = 0;  
       int end = nums.length-1;  
       sort(nums,start,end);  
       System.out.print("快速排序后的结果为：");  
       for(int i:nums){  
            System.out.print(i+" ");  
        }  

    }  

    private static void sort(int[] a,int low,int high){  
        int start = low;  
        int end = high;  
        int key = a[low];  

        while(end>start){                    //从后往前比较  
            while(end>start&&a[end]>=key)   //如果没有比关键值小的，比较下一个，直到有比关键值小的交换位置，然后又从前往后比较  
                end--;  
            if(a[end]<=key){  
                int temp = a[end];  
                a[end] = a[start];  
                a[start] = temp;  
            }  
            //从前往后比较  
            while(end>start&&a[start]<=key)//如果没有比关键值大的，比较下一个，直到有比关键值大的交换位置  
               start++;  
            if(a[start]>=key){  
                int temp = a[start];  
                a[start] = a[end];  
                a[end] = temp;  
            }  
        //  此时第一次循环比较结束，关键值的位置已经确定了。左边的值都比关键值小，右边的值都比关键值大，  
        //  但是两边的顺序还有可能是不一样的，进行下面的递归调用  
        }  

        if(start>low) sort(a,low,start-1);//左边序列。第一个索引位置到关键值索引-1  
        if(end<high) sort(a,end+1,high);//右边序列。从关键值索引+1到最后一个  
    }    
}  

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原文地址：

http://blog.csdn.net/sinat_22797429/article/details/64444248