Java实现几种排序

代码

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import java.util.Random;   
//Java实现的排序类  
public class NumberSort {   
    //私有构造方法，禁止实例化  
    private NumberSort() {   
        super();   
    }    
    //冒泡法排序 
    public static void bubbleSort(int[] numbers) {   
        int temp; // 记录临时中间值   
        int size = numbers.length; // 数组大小   
        for (int i = 0; i < size - 1; i++) {   
            for (int j = i + 1; j < size; j++) {   
                if (numbers[i] < numbers[j]) { // 交换两数的位置   
                    temp = numbers[i];   
                    numbers[i] = numbers[j];   
                    numbers[j] = temp;   
                }   
            }   
        }   
    }   
    //快速排序
    public static void quickSort(int[] numbers, int start, int end) {   
        if (start < end) {   
            int base = numbers[start]; // 选定的基准值（第一个数值作为基准值）   
            int temp; // 记录临时中间值   
            int i = start, j = end;   
            do {   
                while ((numbers[i] < base) && (i < end))   
                    i++;   
                while ((numbers[j] > base) && (j > start))   
                    j--;   
                if (i <= j) {   
                    temp = numbers[i];   
                    numbers[i] = numbers[j];   
                    numbers[j] = temp;   
                    i++;   
                    j--;   
                }   
            } while (i <= j);   
            if (start < j)   
                quickSort(numbers, start, j);   
            if (end > i)   
                quickSort(numbers, i, end);   
        }   
    }   
    //选择排序 
    public static void selectSort(int[] numbers) {   
        int size = numbers.length, temp;   
        for (int i = 0; i < size; i++) {   
            int k = i;   
            for (int j = size - 1; j > i; j--) {   
                if (numbers[j] < numbers[k])   
                    k = j;   
            }   
            temp = numbers[i];   
            numbers[i] = numbers[k];   
            numbers[k] = temp;   
        }   
    }   
    //插入排序    
    // @param numbers  
    public static void insertSort(int[] numbers) {   
        int size = numbers.length, temp, j;   
        for (int i = 1; i < size; i++) {   
            temp = numbers[i];   
            for (j = i; j > 0 && temp < numbers[j - 1]; j--)   
                numbers[j] = numbers[j - 1];   
            numbers[j] = temp;   
        }   
    }   
    //归并排序  
    public static void mergeSort(int[] numbers, int left, int right) {   
        int t = 1;// 每组元素个数   
        int size = right - left + 1;   
        while (t < size) {   
            int s = t;// 本次循环每组元素个数   
            t = 2 * s;   
            int i = left;   
            while (i + (t - 1) < size) {   
                merge(numbers, i, i + (s - 1), i + (t - 1));   
                i += t;   
            }   
            if (i + (s - 1) < right)   
                merge(numbers, i, i + (s - 1), right);   
        }   
    }    
    //归并算法实现  
    private static void merge(int[] data, int p, int q, int r) {   
        int[] B = new int[data.length];   
        int s = p;   
        int t = q + 1;   
        int k = p;   
        while (s <= q && t <= r) {   
            if (data[s] <= data[t]) {   
                B[k] = data[s];   
                s++;   
            } else {   
                B[k] = data[t];   
                t++;   
            }   
            k++;   
        }   
        if (s == q + 1)   
            B[k++] = data[t++];   
        else  
            B[k++] = data[s++];   
        for (int i = p; i <= r; i++)   
            data[i] = B[i];   
    }   
  
}