Longest Word in Dictionary through Deleting

题目地址：
https://leetcode.com/problems/longest-word-in-dictionary-through-deleting/description/

题目：

Given a string and a string dictionary, find the longest string in the dictionary that can be formed by deleting some characters of the given string. If there are more than one possible results, return the longest word with the smallest lexicographical order. If there is no possible result, return the empty string.

Example 1:

Input:
s = "abpcplea", d = ["ale","apple","monkey","plea"]

Output: 
"apple"

Example 2:

Input:
s = "abpcplea", d = ["a","b","c"]

Output: 
"a"

解题思路：
这道题的思路就是先找到一个potential的解，然后再一步一步找更优的解。
Link: http://www.blogjava.net/hgc-ghc/archive/2013/03/28/397084.html

代码：

public String findLongestWord(String s, List<String> d) {
    String res = "";
    for(String w: d){
        if(isSubsequence(w, s)){
            if(w.length() > res.length()) res = w;
            if(w.length() == res.length() && w.compareTo(res) < 0) res = w;
        }
    }
    return res;
}

boolean isSubsequence(String w, String s){
    char[] wc = w.toCharArray();
    char[] sc = s.toCharArray();
    int i = 0, j = 0;
    while(i < wc.length && j < sc.length){
        if(wc[i] == sc[j]) i++;
        j++;
    }
    return i == wc.length;
}