题目:原题链接(中等)
标签:链表、栈、栈-单调栈
解法 | 时间复杂度 | 空间复杂度 | 执行用时 |
---|---|---|---|
Ans 1 (Python) | 404ms (27.93%) | ||
Ans 2 (Python) | 352ms (85.11%) | ||
Ans 3 (Python) |
LeetCode的Python执行用时随缘,只要时间复杂度没有明显差异,执行用时一般都在同一个量级,仅作参考意义。
解法一:
def nextLargerNodes(self, head: ListNode) -> List[int]:
stack = []
ans = []
idx = 0
while head:
ans.append(0)
while stack and head.val > stack[-1][0]:
ans[stack.pop()[1]] = head.val
stack.append([head.val, idx])
idx += 1
head = head.next
return ans
解法二(逆序):
def nextLargerNodes(self, head: ListNode) -> List[int]:
values = []
while head:
values.append(head.val)
head = head.next
stack = []
for i in range(len(values) - 1, -1, -1):
while stack and values[i] >= stack[-1]:
stack.pop()
stack.append(values[i])
if len(stack) > 1:
values[i] = stack[-2]
else:
values[i] = 0
return values