Is Subsequence
Given two strings s and t, return true if s is a subsequence of t, or false otherwise.
A subsequence of a string is formed by deleting zero or more characters from the original string without changing the relative order of the remaining characters.
Example 1
Input
abc ahbgdc
Output
true
Explanation
The characters 'a', 'b', and 'c' appear in the same relative order in the string "ahbgdc".
Therefore, "abc" is a subsequence of "ahbgdc".
Example 2
Input
axc ahbgdc
Output
false
Explanation
The character 'x' does not appear in the string "ahbgdc", so "axc" is not a subsequence.
Constraints
Hints:
Hint 1
Use one pointer for s and another for t.
Hint 2
Traverse t from left to right. Whenever characters match, move the pointer in s. If you reach the end of s, then s is a subsequence of t.
Follow-up
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Author & Technical Reviewer
Technically reviewed by: ExamAdda Technical Review Team
Technical Reviewers, ExamAdda
Software engineers at ExamAdda who check every article's definitions, complexity claims and code examples before and after publishing.
Published
Aug 4, 2026
Last updated
Aug 6, 2026
Content Verification Methodology
Definitions and complexity claims were checked against authoritative computer-science references. Code examples were compiled and tested with standard, boundary and edge-case inputs.
Expected Output