【Java】實現一個遞迴和非遞迴的reverse，它們能把一個表翻轉過來。__Java

【Java】實現一個遞迴和非遞迴的reverse，它們能把一個表翻轉過來。操作中不要建立新的表項，只用已有的項。（表使用LinkedList<Integer>）

1.代碼實現

package devin.wu.readbook;import java.util.LinkedList;public class ReverseTools{public static void reverse(LinkedList<Integer> list, int i){int size = list.size();if (i < size / 2){swapItemByIndex(list, i, size - 1 - i);reverse(list, i + 1);}}public static void reverse(LinkedList<Integer> list){int size = list.size();for (int i = 0; i < size / 2; i++){swapItemByIndex(list, i, size - 1 - i);}}private static void swapItemByIndex(LinkedList<Integer> list, int i, int j){list.set(i, list.get(i) + list.get(j));list.set(j, list.get(i) - list.get(j));list.set(i, list.get(i) - list.get(j));}public static void main(String[] args){LinkedList<Integer> list = new LinkedList<Integer>();list.add(1);list.add(2);list.add(3);list.add(4);list.add(5);System.out.println("-------------To print the initial linked list.--------------------");printLinkedList(list);System.out.println("-------------After reversing by recursion.--------------------");reverse(list);printLinkedList(list);System.out.println("-------------After reversing by iteration.--------------------");reverse(list, 0);printLinkedList(list);}private static void printLinkedList(LinkedList<Integer> list){for (Integer element : list){System.out.println(element);}}}

2.運行效果

-------------To print the initial linked list.--------------------
1
2
3
4
5
-------------After reversing by recursion.--------------------
5
4
3
2
1
-------------After reversing by iteration.--------------------
1
2
3
4
5