Is A String a Substring of Another String?

Fri, 20 Dec 2024 00:00:00 +0000

Problem: Given two strings s and t, return True if s is a subsequence of t, or False otherwise.

Testing Function

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from typing import Callable


def test(approach: Callable[[str, str], bool]) -> None:
 test1 = approach("abc", "ahbgdc") == True
 test2 = approach("axc", "ahbgdc") == False
 status = "Pass" if test1 and test2 else "Fail"
 print(f">>> Result: `{approach.__name__}` - {status}")

Brute Force Approach

A sequence implies that order matters. Therefore, we’ll be traversing t and checking if we can find the characters of s in order. The order here helps and it immediately makes me think that a two-pointer technique is a good fit. I think it is often helpful to imagine what the brute force solution looks like. In this case, we’d be checking every possible subsequence of t to see if it matches s.

LeetCode on Thomas Pinder

Is A String a Substring of Another String?

Brute Force Approach