leetcode 数据结构和算法 demo.zip

package round01.java; public class Code03_Swap_Nodes_In_Pairs { public ListNode swapPairs(ListNode head) { ListNode dummy = new ListNode(0); dummy.next = head; ListNode point = dummy; while (point.next != null && point.next.next != null) { ListNode node1 = point.next; ListNode node2 = point.next.next; point.next = node2; node1.next = node2.next; node2.next = node1; point = node1; } return dummy.next; } static class ListNode { int val; ListNode next; ListNode(int x) { val = x; } @Override public String toString() { StringBuilder temp = new StringBuilder("[" + val); ListNode tempNode = next; while (tempNode != null) { temp.append(", ").append(tempNode.val); tempNode = tempNode.next; } temp.append("]"); return temp.toString(); } } public static void main(String[] args) { ListNode head = new ListNode(1); ListNode node1 = new ListNode(2); ListNode node2 = new ListNode(3); ListNode node3 = new ListNode(4); ListNode node4 = new ListNode(5); head.next = node1; node1.next = node2; node2.next = node3; node3.next = node4; System.out.println(head); ListNode result = new Code03_Swap_Nodes_In_Pairs().swapPairs(head); System.out.println(result); } }