Two Pointers· 15 min

Is Subsequence

LeetCode #392 · Easy · Interactive step-by-step visualization

Setup

Example inputs = "abc", t = "ahbgdc"
Step 1 / 13

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Compare 'a' with 'a'. The source pointer advances only when its required character is found. Characters match.

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is-subsequence.java
1public boolean isSubsequence(String s, String t) {
2    int source = 0;
3    for (int target = 0; target < t.length() && source < s.length(); target++) {
4        if (s.charAt(source) == t.charAt(target))
5            source++;
6    }
7    return source == s.length();
8}
● Java
Time
O(n)
Space
O(1)
Pattern
two pointers
Frames
13
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