# Program to find circular greater element to the right in Python

Suppose we have a list of numbers called nums. We have to find a new list of the same length where the value at index i is assigned to the next element greater than nums[i] to its right, circling back to the front of the list when required. If there is no number that is greater, then it should be set to -1.

So, if the input is like [4, 5, 1, 3], then the output will be [5, -1, 3, 4]

To solve this, we will follow these steps−

• n := size of a

• stack := a stack, insert 0 initially, res := a list of size n and fill with -1

• for each value in range 0 and 1, do

• for i in range 0 to n-1, do

• while stack is not empty and a[top of stack] < a[i], do

• res[top of stack] := a[i]

• delete last element from stack

• insert i at the end of stack

• return res

Let us see the following implementation to get better understanding −

## Example

Live Demo

class Solution:
def solve(self, a):
n = len(a)
stack, res = , [-1] * n
for _ in range(2):
for i in range(n):
while stack and a[stack[-1]] < a[i]:
res[stack[-1]] = a[i]
stack.pop()
stack.append(i)
return res
ob = Solution()
nums = [4, 5, 1, 3]
print(ob.solve(nums))

## Input

[4, 5, 1, 3]

## Output

[5, -1, 3, 4]