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?
Credits:
Special thanks to @pbrother for adding this problem and creating all test cases.
class Solution { public boolean isSubsequence(String s, String t) { if (t.length() == 0 && s.length() == 0) return true; if(s.length() == 0) return true; if(t.length() == 0) return false; int ind = 0; for(int i = 0; i < t.length(); i++){ if(s.charAt(ind) == t.charAt(i)){ if(ind == s.length() - 1) return true; ind++; } } return false; } }
非dp方法，匹配完就是true，匹配不完就是false
然后试了两个dp还memory limit了草