leetcode刷题系列----模式1（Two Points 双指针）- 141：Longest Word in Dictionary through Deleting (Medium) 通过删除字母-优快云博客

leetcode刷题系列----模式1（Two Points 双指针）- 141：Longest Word in Dictionary through Deleting (Medium) 通过删除字母匹配字典里最长单词

Tips

更多题解请见本系列目录
Java和C#核心代码完全一样, length() and Length, compareTo() and CompareTo(), for and foreach
这题比较简单，遍历字符串数组后使用双指针比较目标字符s与字符串数组内的元素。
在类内额外定义一个双指针的字符串是否属于子串的函数，代码逻辑结构会更清晰。

Python

class Solution:
    def findLongestWord(self, s: str, dictionary: List[str]) -> str:
        result = ''
        for item in dictionary:
            p_item = p_s = 0
            while p_item<len(item) and p_s<len(s):
                if s[p_s]==item[p_item]:
                    p_item += 1
                p_s += 1
            
            
            if p_item==len(item):
                if len(item)>len(result) or (len(item)==len(result) and result>item):
                    result = item
        
        return result

C++

class Solution {
public:
    string findLongestWord(string s, vector<string>& dictionary) {
        string longestWord = "";
        for(string target : dictionary)
        {
            int l1=longestWord.size(), l2=target.size();
            if(l1>l2 || (l1==l2 && longestWord.compare(target)<0)) continue;
            if(isSubstr(s, target)) longestWord = target;
        }
        return longestWord;
    }

private:
    bool isSubstr(string s, string target) {
        int i = 0, j = 0;
        while (i < s.length() && j < target.length()) {
            if (s[i] == target[j]) {
                j++;
            }
            i++;
        }
        return j == target.length();
    }

};

C#

public class Solution {
    public string FindLongestWord(string s, IList<string> dictionary) {
        string longestWord = "";
        foreach(string target in dictionary)
        {
            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 bool isSubstr(string s, string target) {
        int i = 0, j = 0;
        while (i < s.Length && j < target.Length) {
            if (s[i] == target[j]) {
                j++;
            }
            i++;
        }
        return j == target.Length;
    }
}

Java

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();
    }

}