leetcode524

public class Solution {
    public string FindLongestWord(string s, IList<string> d) {
        string longest = "";
            foreach (var dictWord in d)
            {
                int i = 0;
                foreach (var c in s)
                {
                    if (i < dictWord.Length && c == dictWord[i])
                    {
                        i++;
                    }
                }

                if (i == dictWord.Length && dictWord.Length >= longest.Length)
                {
                    if (dictWord.Length > longest.Length || dictWord.CompareTo(longest) < 0)
                    {
                        longest = dictWord;
                    }
                }
            }
            return longest;
    }
}

https://leetcode.com/problems/longest-word-in-dictionary-through-deleting/#/description

补充一个python的实现：

class Solution:
    def findLongestWord(self, s: str, d: 'List[str]') -> str:
        maxlen = 0
        longestword = ''
        for sd in d:            
            curlen = 0
            i=0
            j=0
            while i<len(s) and j<len(sd):
                if s[i]==sd[j]:
                    curlen += 1
                    if curlen == len(sd):
                        if curlen > maxlen or (curlen == maxlen and sd<longestword):
                            maxlen = curlen
                            longestword = sd

                        break
                    else:
                        i+=1
                        j+=1
                else:
                    i+=1
        return longestword

再补充一个java实现：

class Solution {
    public String findLongestWord(String s, List<String> d) {
        String longestWord = "";
        for (String target : d) {
            int l1 = longestWord.length(), l2 = target.length();
            if (l1 > l2 || (l1 == l2 && longestWord.compareTo(target) < 0)) {
                continue;
            }
            if (isSubstr(s, target)) {
                longestWord = target;
            }
        }
        return longestWord;
    }

    private boolean isSubstr(String s, String target) {
        int i = 0, j = 0;
        while (i < s.length() && j < target.length()) {
            if (s.charAt(i) == target.charAt(j)) {
                j++;
            }
            i++;
        }
        return j == target.length();
    }
}