插入排序

插入排序的效率：O(N*N), 比较N*N/4，复制N*N/4，插入排序在随机数的情况下，比冒泡快一倍，比选择稍快，在基本有序的数组中，插入排序几乎只需要O(N)，在逆序的情况下，并不比冒泡快。

代码：

package sorts;

public class InsertionSort {
    /**
     * @param a the array
     * @param low the lower bound (inclusive)
     * @param high the upper bound (exclusive)
     * */
    public static <T extends Comparable<T>> void sort(T[] a, int low, int high) {
        --high;
        for (int i = low+1; i <= high; i++) { // index from  the second character in a
            T cur = a[i]; // the current character to  be inserted
            int j = i - 1; // start comparing with cell left of i
            while ((j>=low) && (a[j].compareTo(cur) > 0)) { // while a[j]  is  out of order with cur
                a[j+1] = a[j];
                j = j - 1;
            }
            a[j+1] = cur;
        }
    }
}