INSERTION-SORT(A)for j = 2 to A.lengthkey = A[j]　　　　// 将桌面的牌拿至右手i = j -1　　　　　// 左手中已经排序好的牌的数量while i > 0 and A[i] > key　　　　// 将右手中的key牌与左手中的牌从右到左进行比较A[i+1] = A[i]i = i - 1A[i+1] = key　　　　// 将右手中的牌插入到左手中

import java.util.ArrayList;
/** * 作者原创，引用请注明出处 * @author ChameleonChen */
public abstract class InsertionSort<T> {public static final int A_GREATER_THAN_B = 1;public static final int A_LESS_THAN_B = 2;public static final int A_EQUALS_B = 3;/*** 实现a b 两个元素的比较策略。* ex:*     int elemCompare(Integer a, Integer b) {*         if (a > b) return InsertionSort.A_GREATER_THAN_B;*         else if (a < b) return InsertionSort.A_LESS_THAN_B;*         else return InsertionSort.A_EQUALS_B;*     }* @param a* @param b* @return a大于b，返回InsertionSort.A_GREATER_THAN_B；a小于b，返回InsertionSort.A_LESS_THAN_B*         a等于b，返回InsertionSort.A_EQUALS_B.*/public abstract int elemCompare(T a, T b);  public static final int NON_DECREASING_SORT = 1;    // 非递减排序public static final int NON_INCREASING_SORT = 2;    // 非递增排序/*** 对elems进行排序，改变其在内存中的值。* 实现算法如下：* INSERTION-SORT(A)*   for j = 2 to A.length*       key = A[j]*   *       i = j - 1*       while i > 0 and A[i] > key*           A[i+1] = A[i]*           i = i - 1*       A[i+1] = key* * @param elems* @param sortType 排序的类型：非递减排序 InsertionSort.NON_DECREASING_SORT；* 非递增排序InsertionSort.NON_INCREASING_SORT*/public void sort(ArrayList<T> elems, int sortType) {if (elems == null){throw new NullPointerException("the elems can not be null");}int expected;switch (sortType) {case NON_DECREASING_SORT:expected = A_GREATER_THAN_B;break;case NON_INCREASING_SORT:expected = A_LESS_THAN_B;break;default :throw new IllegalArgumentException("the sortType's value is illegal");}T temp;for (int j=1,i; j<elems.size(); j++) {temp = elems.get(j);i = j - 1;while (i>=0 && elemCompare(elems.get(i), temp) == expected) {elems.set(i+1, elems.get(i));i = i - 1;}elems.set(i+1, temp);}}
}