524. Longest Word in Dictionary through Deleting

最新推荐文章于 2025-08-20 09:37:41 发布

SnailRunFast

最新推荐文章于 2025-08-20 09:37:41 发布

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分类专栏： Leet Code 文章标签： leetcode Longest Word in Dict

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本文介绍了一种算法，用于从给定字符串中找到字典中最长的子序列字符串。通过遍历字典中的每个单词，并检查这些单词是否可以通过删除给定字符串的一些字符来形成，从而确定最长且字典序最小的匹配项。

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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"

Note:

All the strings in the input will only contain lower-case letters.
The size of the dictionary won't exceed 1,000.
The length of all the strings in the input won't exceed 1,000.

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Solution:

Tips: just record the max length and its result. when the max length is equal with last one, then compare the result, then take the small one.

Java Code:

public class Solution {
    public String findLongestWord(String s, List<String> d) {
        if (null == d || d.isEmpty()) {
            return "";
        }
        String result = "";
        int maxLen = 0;
        for (String str : d) {
            if (str.length() > s.length()) {
                continue;
            }
            
            int i = 0, j = 0;
            while (i < s.length() && j < str.length()) {
                if (s.charAt(i) == str.charAt(j)) {
                    j++;
                }
                i++;
            }
            
            if (j == str.length() && j >= maxLen) {
                if (result.isEmpty()) {
                    result = str;
                    maxLen = j;
                    continue;
                }
                result = (j > maxLen || result.compareTo(str) > 0) ? str : result;
                maxLen = j;
            }
        }
        
        return result;
    }
}