双指针
class Solution {public boolean isSubsequence(String s, String t) {int i = 0, j = 0;while (i < s.length() && j < t.length()) {if (s.charAt(i) != t.charAt(j)) {++j;} else {++i;++j;}}if (i == s.length()) return true;else return false;}
}
*有余力可以看看拓展版