/**
  * 选择排序 时间复杂度 O(n2)
  * */
 public static int[] selectSort(int[] ary) {
    for (int i = 0; i < ary.length - 1; i++) {
         for (int j = i + 1; j < ary.length; j++) {
             if (ary[i] > ary[j]) {
                 int t = ary[i];
                 ary[i] = ary[j];
                 ary[j] = t;
             }
         }
     }
     return ary;
 }
     /**
  * 冒泡排序 时间复杂度 O(n2)
  * */
 public static int[] bubbleSort(int[] ary) {
     for (int i = 0; i < ary.length - 1; i++) {
         for (int j = 0; j < ary.length - i - 1; j++) {
             if (ary[j] > ary[j + 1]) {
                 int t = ary[j];
                 ary[j] = ary[j + 1];
                 ary[j + 1] = t;
             }
         }
     }
     return ary;
 }
/**
  * 插入排序  时间复杂度 O(n2)
  * */
 public static int[] insertSort(int[] ary) {
     int i, j, t;
     for (i = 1; i < ary.length; i++) {
         t = ary[i];
         //利用循环查找 插入位置：到头j=-1
         for (j = i - 1; j >= 0 && t < ary[j]; j--) {
             ary[j + 1] = ary[j];
         }

         ary[j + 1] = t;
     }
     return ary;
 }