Question

Intuition

Approach

Complexity

• Time complexity: $$O(log\ n)$$

• Space complexity: $$O(1)$$

Code

class Solution:
    def nextGreatestLetter(self, letters: List[str], target: str) -> str:
        if target >= letters[-1]:
            return letters[0]
        smallestSoFar = letters[-1]
        low, high = 0, len(letters) - 1
        while low <= high:
            mid = (low + high) // 2
            if letters[mid] > target:
                smallestSoFar = letters[mid]
                high = mid - 1
            else:
                low = mid + 1
        return smallestSoFar
        

Result