从单链表中删除节点

class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next

def deleteNode(head, val):
    # 处理头节点为要删除节点的情况
    if head.val == val:
        return head.next
    
    # 遍历链表查找要删除的节点
    curr = head
    while curr.next:
        if curr.next.val == val:
            curr.next = curr.next.next
            break
        curr = curr.next
    
    return head

# 创建一个示例链表：1 -> 2 -> 3 -> 4 -> 5
head = ListNode(1)
node2 = ListNode(2)
node3 = ListNode(3)
node4 = ListNode(4)
node5 = ListNode(5)
head.next = node2
node2.next = node3
node3.next = node4
node4.next = node5

# 删除节点值为3的节点
head = deleteNode(head, 3)

# 打印删除节点后的链表：1 -> 2 -> 4 -> 5
curr = head
while curr:
    print(curr.val)
    curr = curr.next