class Solution(object):
    def nextGreaterElements(self, nums):
        """
        :type nums: List[int]
        :rtype: List[int]
        """
        stack = []
        peeks = [-1] * len(nums)
        for i in range(len(nums)) * 2:
            while stack and nums[stack[-1]] < nums[i]:
                peeks[stack.pop()] = nums[i]
            stack.append(i)
        res = []
        for i, num in enumerate(nums):
            res.append(peeks[i])
        return res