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T8.java
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56 lines (48 loc) · 1.43 KB
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package testCode;
public class T8 {
static class ListNode {
int val;
ListNode next;
ListNode(int x) {
val = x;
next = null;
}
}
public static final void main(String args[]) {
ListNode head = new ListNode(1);
head.next = new ListNode(2);
head.next.next = new ListNode(3);
head.next.next.next = new ListNode(4);
reorderList(head);
System.out.print(head.val + " " + head.next.next.next.val);
}
public static void reorderList(ListNode head) {
if (null == head || null == head.next) {
return;
}
ListNode slowPtr = head;
ListNode fastPtr = head;
while (null != fastPtr.next && null != fastPtr.next.next) {
slowPtr = slowPtr.next;
fastPtr = fastPtr.next.next;
}
ListNode startPtr = slowPtr.next;
ListNode headPtr = startPtr;
slowPtr.next = null;
while (null != headPtr.next) {
ListNode tempPtr = headPtr.next;
headPtr.next = tempPtr.next;
tempPtr.next = startPtr;
startPtr = tempPtr;
}
ListNode l1 = head;
ListNode l2 = startPtr;
while (null != l1 && null != l2) {
ListNode tempPtr = l2;
l2 = l2.next;
tempPtr.next = l1.next;
l1.next = tempPtr;
l1 = l1.next.next;
}
}
}