https://leetcode.com/problems/is-subsequence/

SubSequence.java

package jp.vietpro.vta;

public class SubSequence {
  public static boolean isSubsequence(String s, String t) {
    if(s.length()==0)
      return true;
    int sI=0;

    for (int tI=0; tI < t.length(); tI++ ){
      if (t.charAt(tI) == s.charAt(sI)){
        sI++;
      }
      if(sI >= s.length()){
        return true;
      }
    }

    return false;
  }
}