Next greater element

• This can be solved using Hashmap or Stack
• Challenge is to solve it without using extra space.

Hashmap

# Python3 code
class Solution:
	def nextLargerElement(self, arr, n):
		# code here
		s = []
		for i in range(len(arr)):
			while s and s[-1].get("value") < arr[i]:
				d = s.pop()
				arr[d.get("ind")] = arr[i]
			s.append({"value": arr[i], "ind": i})
		while s:
			d = s.pop()
			arr[d.get("ind")] = -1
		return arr
 
 
if __name__ == "__main__":
	print(Solution().nextLargerElement([6, 8, 0, 1, 3], 5))