笔试：基本排序方法

  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 }