笔试：基本排序方法

转载自：http://www.cnblogs.com/sevenyuan/archive/2009/12/04/1616897.html

冒泡排序、快速排序、选择排序、插入排序、希尔排序，甚至还有基数排序、鸡尾酒排序、桶排序、鸽巢排序、归并排序等。

  1 代码
  2
  3 Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->package test.sort;
  4 import java.util.Random;
  5 //Java实现的排序类
  6 public class NumberSort {
  7     //私有构造方法，禁止实例化
  8     private NumberSort() {
  9         super();
 10     }
 11     //冒泡法排序
 12     public static void bubbleSort(int[] numbers) {
 13         int temp; // 记录临时中间值
 14         int size = numbers.length; // 数组大小
 15         for (int i = 0; i < size - 1; i++) {
 16             for (int j = i + 1; j < size; j++) {
 17                 if (numbers[i] < numbers[j]) { // 交换两数的位置
 18                     temp = numbers[i];
 19                     numbers[i] = numbers[j];
 20                     numbers[j] = temp;
 21                 }
 22             }
 23         }
 24     }
 25     //快速排序
 26     public static void quickSort(int[] numbers, int start, int end) {
 27         if (start < end) {
 28             int base = numbers[start]; // 选定的基准值（第一个数值作为基准值）
 29             int temp; // 记录临时中间值
 30             int i = start, j = end;
 31             do {
 32                 while ((numbers[i] < base) && (i < end))
 33                     i++;
 34                 while ((numbers[j] > base) && (j > start))
 35                     j--;
 36                 if (i <= j) {
 37                     temp = numbers[i];
 38                     numbers[i] = numbers[j];
 39                     numbers[j] = temp;
 40                     i++;
 41                     j--;
 42                 }
 43             } while (i <= j);
 44             if (start < j)
 45                 quickSort(numbers, start, j);
 46             if (end > i)
 47                 quickSort(numbers, i, end);
 48         }
 49     }
 50     //选择排序
 51     public static void selectSort(int[] numbers) {
 52         int size = numbers.length, temp;
 53         for (int i = 0; i < size; i++) {
 54             int k = i;
 55             for (int j = size - 1; j > i; j--) {
 56                 if (numbers[j] < numbers[k])
 57                     k = j;
 58             }
 59             temp = numbers[i];
 60             numbers[i] = numbers[k];
 61             numbers[k] = temp;
 62         }
 63     }
 64     //插入排序
 65     // @param numbers
 66     public static void insertSort(int[] numbers) {
 67         int size = numbers.length, temp, j;
 68         for (int i = 1; i < size; i++) {
 69             temp = numbers[i];
 70             for (j = i; j > 0 && temp < numbers[j - 1]; j--)
 71                 numbers[j] = numbers[j - 1];
 72             numbers[j] = temp;
 73         }
 74     }
 75     //归并排序
 76     public static void mergeSort(int[] numbers, int left, int right) {
 77         int t = 1;// 每组元素个数
 78         int size = right - left + 1;
 79         while (t < size) {
 80             int s = t;// 本次循环每组元素个数
 81             t = 2 * s;
 82             int i = left;
 83             while (i + (t - 1) < size) {
 84                 merge(numbers, i, i + (s - 1), i + (t - 1));
 85                 i += t;
 86             }
 87             if (i + (s - 1) < right)
 88                 merge(numbers, i, i + (s - 1), right);
 89         }
 90     }
 91     //归并算法实现
 92     private static void merge(int[] data, int p, int q, int r) {
 93         int[] B = new int[data.length];
 94         int s = p;
 95         int t = q + 1;
 96         int k = p;
 97         while (s <= q && t <= r) {
 98             if (data[s] <= data[t]) {
 99                 B[k] = data[s];
100                 s++;
101             } else {
102                 B[k] = data[t];
103                 t++;
104             }
105             k++;
106         }
107         if (s == q + 1)
108             B[k++] = data[t++];
109         else
110             B[k++] = data[s++];
111         for (int i = p; i <= r; i++)
112             data[i] = B[i];
113     }
114
115 }