[LeetCode] Longest Word in Dictionary

econi 發布于2019-08-19 11:06 / 2503人閱讀

Problem

Given a list of strings words representing an English Dictionary, find the longest word in words that can be built one character at a time by other words in words. If there is more than one possible answer, return the longest word with the smallest lexicographical order.

If there is no answer, return the empty string.
Example 1:
Input:

words = ["w","wo","wor","worl", "world"]

Output:

"world"

Explanation:
The word "world" can be built one character at a time by "w", "wo", "wor", and "worl".
Example 2:
Input:

words = ["a", "banana", "app", "appl", "ap", "apply", "apple"]

Output:

"apple"

Explanation:
Both "apply" and "apple" can be built from other words in the dictionary. However, "apple" is lexicographically smaller than "apply".
Note:

All the strings in the input will only contain lowercase letters.
The length of words will be in the range [1, 1000].
The length of words[i] will be in the range [1, 30].

Solution

class Solution {
    class Trie {
        Node root;
        class Node {
            boolean isWord;
            Node[] children = new Node[26];
        }
        
        public Trie() {
            root = new Node();
            root.isWord = true;
        }
        
        void insert (String str) {
            Node node = root;
            for (char ch: str.toCharArray()) {
                int index = ch - "a";
                if (node.children[index] == null) {
                    node.children[index] = new Node();
                }
                node = node.children[index];
            }
            node.isWord = true;
        }
        
        boolean hasWord(String word) {
            Node node = root;
            for (char ch: word.toCharArray()) {
                int index = ch - "a";
                if (node.children[index] == null || !node.isWord) return false;
                node = node.children[index];
            }
            return true;
        }
    }
    public String longestWord(String[] words) {
        Trie trie = new Trie();
        for (String word: words) {
            trie.insert(word);
        }
        String res = "";
        for (String word: words) {
            if (trie.hasWord(word) && 
               (word.length() > res.length() || (word.length() == res.length() && word.compareTo(res) < 0))) {
                res = word;
            }
        }
        return res;
    }
}

云服務器 GPU云服務器 Longest Dictionary Dictionary遍歷 LeetCode

文章版權歸作者所有，未經允許請勿轉載,若此文章存在違規行為，您可以聯系管理員刪除。

轉載請注明本文地址：http://specialneedsforspecialkids.com/yun/77001.html

[LintCode] Longest Words

Problem Given a dictionary, find all of the longest words in the dictionary. Example Given { dog, google, facebook, internationalization, blabla } the longest words are(is) [internationaliz...

roadtogeek 2019-08-14 15:15 評論0 收藏0
[Leetcode] Word Break 單詞分解

摘要：所以只要驗證滿足這個條件，我們則可以確定這個較長的字符串也是可分解的。同時，我們用數組記錄下字符串長度遞增時可分解的情況，以供之后使用，避免重復計算。當遍歷完這個詞典并找出所有以第一個字母開頭的詞以后，我們進入下一輪搜索。 Word Break I Given a string s and a dictionary of words dict, determine if s can ...

Ververica 2019-08-14 12:24 評論0 收藏0
leetcode140. Word Break II

摘要：題目要求現在有一個非空字符串和一個非空的字典。現在向中添加空格從而構成一個句子，其中這個句子的所有單詞都存在與中。題目要求 Given a non-empty string s and a dictionary wordDict containing a list of non-empty words, add spaces in s to construct a sentence ...

huayeluoliuhen 2019-08-15 14:29 評論0 收藏0
[Leetcode] Alien Dictionary 外文字典

摘要：拓撲排序復雜度時間空間思路首先簡單介紹一下拓撲排序，這是一個能夠找出有向無環圖順序的一個方法假設我們有條邊，先將每個節點的計數器初始化為。最后，我們開始拓撲排序，從計數器為的字母開始廣度優先搜索。 Alien Dictionary There is a new alien language which uses the latin alphabet. However, the ord...

pkhope 2019-08-14 12:38 評論0 收藏0
[leetcode] Minimum Window Substring

摘要：使用而不是因為我們需要的是最值，中間值我們不在乎，所以一次收斂到最小。下面來三個需要查重并且記錄上次出現的位置，選擇以為例，走到用做檢查，發現出現過，把移到的下一個。是上個題目的簡易版，或者特殊版。這里聊一聊解一類問題，就是滿足某一條件的substring最值問題。最開始我們以Minimum Window Substring為例，并整理總結leetcode里所有類似題目的通解。 Gi...

Pines_Cheng 2019-08-14 17:17 評論0 收藏0