392. Is Subsequence

https://leetcode.com/problems/is-subsequence/description/
解题思路：

1. 判断s和t的字符是否相等

class Solution {
public boolean isSubsequence(String s, String t) {

    int sLen = s.length(), tLen = t.length(), sIndex = 0;
    for(int i = 0; i < tLen && sIndex < sLen; i++){
       if(t.charAt(i) == s.charAt(sIndex)){
           sIndex++;
       }
    }
    return sIndex == sLen;
}

}