Total Accepted: 9572
Total Submissions: 21748
Difficulty: Medium
Given a string s and a string t, check if s is subsequence of t.
You may assume that there is only lower case English letters in both s and t. t is potentially a very long (length ~= 500,000) string, and s is a short string (<=100).
A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without disturbing the relative positions of the remaining characters. (ie, "ace"
is a subsequence of "abcde"
while "aec"
is not).
Example 1:****s = "abc"
, t = "ahbgdc"
Return true
.
Example 2:****s = "axc"
, t = "ahbgdc"
Return false
.
Follow up:If there are lots of incoming S, say S1, S2, ... , Sk where k >= 1B, and you want to check one by one to see if T has its subsequence. In this scenario, how would you change your code?
// use two pointers
// https://discuss.leetcode.com/topic/57147/straight-forward-java-simple-solution
public boolean isSubsequence(String s, String t) {
if ( s.length() == 0) return true;
int i = 0, j = 0; // index of s, t
while (j < t.length()) {
if (s.charAt(i) == t.charAt(j) ) {
i++;
}
if (i == s.length()) return true;
j++;
}
return false;
}
