Linked List Random Node
Intuition
Solution
class Solution:
def __init__(self, head: ListNode):
"""
@param head The linked list's head.
Note that the head is guaranteed to be not null, so it contains at least one node.
"""
self.head = head
self.n = 0
index = self.head
while index is not None:
self.n += 1
index = index.next
def getRandom(self) -> int:
"""
Returns a random node's value.
"""
n = random.randint(0, self.n - 1)
index = self.head
for _ in range(n):
index = index.next
return index.val
# Your Solution object will be instantiated and called as such:
# obj = Solution(head)
# param_1 = obj.getRandom()