算法题刷题笔记-链表

1. 相交链表（LC160）

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# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def getIntersectionNode(self, headA: ListNode, headB: ListNode) -> Optional[ListNode]:
        A = headA
        B = headB
        while A != B:
            A = A.next if A else headB
            B = B.next if B else headA
        return A
  • 链表基本操作

2. 反转链表（LC206）

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# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
        pre = None
        cur = head
        while cur:
            nxt = cur.next
            cur.next = pre
            pre = cur
            cur = nxt
        return pre
  • 遍历链表，交换next指针