524. Longest Word in Dictionary through Deleting

陈胖纸

于 2022-06-26 21:07:01 发布

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分类专栏： Leetcode 文章标签： leetcode 算法 java

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此篇博客介绍了如何使用Java编程解决给定字符串s和字典数组dictionary的问题，寻找能够通过删除s中字符形成的最长字典中的单词。如果有多解，返回字典序最小且长度最长的单词，若无解则返回空字符串。关键算法包括双指针判断子集和字符串比较。

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524. Longest Word in Dictionary through Deleting

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

Example 1:

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

Example 2:

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

这里双指针用来判断是不是dictionary的子集，然后用一个比大小来遍历List就可以了。

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