57天【代码随想录算法训练营34期】第十章 单调栈part01

739. 每日温度
单调栈指的是只增加或只减少的stack，相当于一个memo

class Solution:
    def dailyTemperatures(self, temperatures: List[int]) -> List[int]:
        answer = [0] * len(temperatures)
        stack = [0]
        for i in range(1, len(temperatures)):
            while len(stack) != 0 and temperatures[i] > temperatures[stack[-1]]:
                answer[stack[-1]] = i - stack[-1]
                stack.pop(-1)
            stack.append(i)
        return answer

496.下一个更大元素 I

class Solution:
    def nextGreaterElement(self, nums1: List[int], nums2: List[int]) -> List[int]:
        result = [-1] * len(nums1)
        stack = [0]

        for i in range(1, len(nums2)):
            if nums2[i] <= nums2[stack[-1]]:
                stack.append(i)
            else:
                while len(stack) != 0 and nums2[i] > nums2[stack[-1]]:
                    if nums2[stack[-1]] in nums1:
                        index = nums1.index(nums2[stack[-1]])
                        result[index] = nums2[i]
                    stack.pop()
                stack.append(i)
        return result