选择排序基本思路：设个基准，然后通过循环对比找出最小的

时间复杂度：O(n2)

/** *  */package com;/** * @author wenb * @time 下午01:41:21 * @date 2014-10-24 */public class SelectSort {        public static void main(String[] args){                int[] a = {
   1,3,2,21,5,12,98,54};        Select(a);        for(int i=0;i
     
      i;j--){                if(a[j]
     

希尔排序基本思路：将整个无序列分割成若干小的子序列分别进行插入排序

时间复杂度：O(n2)

/** *  */package com;/** * @author wenb * @time 下午02:44:18 * @date 2014-10-24 */    public class ShellSort {                public static void main(String[] args) {                    int[] a = {
   1,3,2,21,5,12,98,54};            shellSort(a);            for (int i = 0; i < a.length; i++) {                  System.out.print(a[i] + " ");              }                  }                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;                       }                  }                  h = (h - 1) / 3;        // 计算出下一个h值              }          }              }

归并排序基本思路：将两个（或两个以上）有序表合并成一个新的有序表 即把待排序序列分为若干个子序列，每个子序列是有序的。然后再把有序子序列合并为整体有序序列 

时间复杂度：O(nlogn)

/** *  */package com;import java.util.Arrays;/** * @author wenb * @time 下午03:41:12 * @date 2014-10-24 */public class MergeSort {    public static void main(String[] args) {             int[] a = {
   1,3,2,21,5,12,98,54};        MergeSort.sort(a, 0, a.length-1);          for (int i = 0; i < a.length; i++) {              System.out.print(a[i] + " ");          }      }        public static int[] sort(int[] nums, int low, int high) {          int mid = (low + high) / 2;          if (low < high) {              // 左边              sort(nums, low, mid);              // 右边              sort(nums, mid + 1, high);              // 左右归并              merge(nums, low, mid, high);          }          return nums;      }        public static void merge(int[] nums, int low, int mid, int high) {          int[] temp = new int[high - low + 1];          int i = low;// 左指针          int j = mid + 1;// 右指针          int k = 0;            // 把较小的数先移到新数组中          while (i <= mid && j <= high) {              if (nums[i] < nums[j]) {                  temp[k++] = nums[i++];              } else {                  temp[k++] = nums[j++];              }          }            // 把左边剩余的数移入数组          while (i <= mid) {              temp[k++] = nums[i++];          }            // 把右边边剩余的数移入数组          while (j <= high) {              temp[k++] = nums[j++];          }            // 把新数组中的数覆盖nums数组          for (int k2 = 0; k2 < temp.length; k2++) {              nums[k2 + low] = temp[k2];          }      }      }