给定一个单链list L : , L → L →…→L → ,
重新排序为:L , → L → L → L → L → L →…
你必须就地在不改变节点的值。例如,
Given <代码>{1,2,3,4}> {1 4 2 3}>
L L L L L
/* *
,* Definition for singly-linked 列表。
,* struct ListNode {
,*,,,,int val;
,*,,,,struct ListNode *下;
,*};
,*/void reorderList (struct ListNode *,头)
{
,,,if (==,, head NULL | |,头→next ==, NULL | |,头→下一步→next ==, NULL )
,,,{
,,,,,,,返回;
,,,}
,,,,
,,,struct ListNode * list ,=,头;
,,,int len =, 0;
,,,while (, list )
,,,{
,,,,,,,list =,列表→下;
,,,,,,,len +=, 1;
,,,}
,,,,
,,,int key =, 0;
,,,if (%, len 2,,==, 0,)
,,,{
,,,,,,,key =, len /, 2;
,,,}
,,,
,,,{
,,,,,,,key =,(时间/len 2), +, 1;
,,,}
,,,,
,,,struct ListNode * second =,头;
,,,list ,=,头;
,,,int cnt =, 0;
,,,while (, cnt & lt;, key )
,,,{
,,,,,,,list =,第二;
,,,,,,,second =,第二→下;
,,,,,,,cnt +=, 1;
,,,}
,,,列表→next =,空;
,,,,
,,,list =,空;
,,,struct ListNode * next =,空;
,,,while (, second )
,,,{
,,,,,,,next =,第二→下;
,,,,,,,第二个→next =,列表;
,,,,,,,list =,第二;
,,,,,,,second =,下一个;
,,,}
,,,second =,列表;
,,,,
,,,next =,空;
,,,while (, second )
,,,{
,,,,,,,next =,第二;
,,,,,,,second =,第二→下;
,,,,,,,下一个→next =,头→下;
,,,,,,,头→next =,下一个;
,,,,,,,head =,头→下一步→下;
,,,}
}
