插入排序

 1 int[] insertionSort(int arr[]) {//插入排序
 2         int preIndex,current;
 3         for(int i = 1; i < arr.length; i++) {
 4             preIndex = i - 1;
 5             current = arr[i];
 6             while (preIndex >= 0 && arr[preIndex] > current) {
 7                 arr[preIndex + 1] = arr[preIndex];
 8                 preIndex--;
 9             }
10             arr[preIndex + 1] = current;
11         }
12         return arr;
13     }