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.
class Solution {
public boolean isSubsequence(String s, String t) {
char[] s_array = s.toCharArray();
int previndex = -1;
int j=0;
for(int i=0;i<t.length();i++){
if(j==s.length()) return true;
if(t.charAt(i) == s.charAt(j)) j++;
}
return j==s.length();
}
}