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3566. Find the Sequence of Strings Appeared on the Screen

My accepted Python solution to LeetCode problem 3566, Find the Sequence of Strings Appeared on the Screen, running in 21ms.

  • Difficulty: Medium
  • Python
  • Runtime 21ms
  • Memory 26.5MB

Read the problem on LeetCode View on GitHub

The problem statement is LeetCode’s and stays on their site. What follows is my accepted solution.

Python

Accepted on LeetCode — runtime 21ms, memory 26.5MB, accepted 2025-12-31.

python
class Solution:
    def stringSequence(self, target: str) -> List[str]:
        result = []
        current = ""
        
        for char in target:
            # First, append 'a' to current string
            current += 'a'
            result.append(current)
            
            # Then change last character until we reach target char
            while current[-1] != char:
                # Increment last character
                current = current[:-1] + chr(ord(current[-1]) + 1)
                result.append(current)
        
        return result

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