国产xxxx99真实实拍_久久不雅视频_高清韩国a级特黄毛片_嗯老师别我我受不了了小说

資訊專欄INFORMATION COLUMN

[LeetCode] 642. Design Search Autocomplete System

MartinHan / 3120人閱讀

Problem

Design a search autocomplete system for a search engine. Users may input a sentence (at least one word and end with a special character "#"). For each character they type except "#", you need to return the top 3 historical hot sentences that have prefix the same as the part of sentence already typed. Here are the specific rules:

The hot degree for a sentence is defined as the number of times a user typed the exactly same sentence before.
The returned top 3 hot sentences should be sorted by hot degree (The first is the hottest one). If several sentences have the same degree of hot, you need to use ASCII-code order (smaller one appears first).
If less than 3 hot sentences exist, then just return as many as you can.
When the input is a special character, it means the sentence ends, and in this case, you need to return an empty list.
Your job is to implement the following functions:

The constructor function:

AutocompleteSystem(String[] sentences, int[] times): This is the constructor. The input is historical data. Sentences is a string array consists of previously typed sentences. Times is the corresponding times a sentence has been typed. Your system should record these historical data.

Now, the user wants to input a new sentence. The following function will provide the next character the user types:

List input(char c): The input c is the next character typed by the user. The character will only be lower-case letters ("a" to "z"), blank space (" ") or a special character ("#"). Also, the previously typed sentence should be recorded in your system. The output will be the top 3 historical hot sentences that have prefix the same as the part of sentence already typed.

Example:
Operation: AutocompleteSystem(["i love you", "island","ironman", "i love leetcode"], [5,3,2,2])
The system have already tracked down the following sentences and their corresponding times:
"i love you" : 5 times
"island" : 3 times
"ironman" : 2 times
"i love leetcode" : 2 times
Now, the user begins another search:

Operation: input("i")
Output: ["i love you", "island","i love leetcode"]
Explanation:
There are four sentences that have prefix "i". Among them, "ironman" and "i love leetcode" have same hot degree. Since " " has ASCII code 32 and "r" has ASCII code 114, "i love leetcode" should be in front of "ironman". Also we only need to output top 3 hot sentences, so "ironman" will be ignored.

Operation: input(" ")
Output: ["i love you","i love leetcode"]
Explanation:
There are only two sentences that have prefix "i ".

Operation: input("a")
Output: []
Explanation:
There are no sentences that have prefix "i a".

Operation: input("#")
Output: []
Explanation:
The user finished the input, the sentence "i a" should be saved as a historical sentence in system. And the following input will be counted as a new search.

Note:
The input sentence will always start with a letter and end with "#", and only one blank space will exist between two words.
The number of complete sentences that to be searched won"t exceed 100. The length of each sentence including those in the historical data won"t exceed 100.
Please use double-quote instead of single-quote when you write test cases even for a character input.
Please remember to RESET your class variables declared in class AutocompleteSystem, as static/class variables are persisted across multiple test cases. Please see here for more details.

Solution
class AutocompleteSystem {
    class TrieNode {
        Map children;
        Map counts;
        boolean isWord;
        public TrieNode() {
            children = new HashMap<>();
            counts = new HashMap<>();
            isWord = false;
        }
    }
    
    class Node {
        String word;
        int count;
        public Node(String s, int c) {
            this.word = s;
            this.count = c;
        }
    }
    
    TrieNode root;
    String prefix;
    
    public AutocompleteSystem(String[] sentences, int[] times) {
        root = new TrieNode();
        prefix = "";
        for (int i = 0; i < sentences.length; i++) {
            add(sentences[i], times[i]);
        }
    }
    
    private void add(String word, int count) {
        TrieNode cur = root;
        for (char ch: word.toCharArray()) {
            TrieNode next = cur.children.get(ch);
            if (next == null) {
                next = new TrieNode();
                cur.children.put(ch, next);
            }
            cur = next;
            cur.counts.put(word, cur.counts.getOrDefault(word, 0)+count);
        }
        cur.isWord = true;
    }
    
    public List input(char c) {
        if (c == "#") {
            add(prefix, 1);
            prefix = "";
            return new ArrayList<>();
        }
        
        prefix += c;
        TrieNode cur = root;
        for (char ch: prefix.toCharArray()) {
            TrieNode next = cur.children.get(ch);
            if (next == null) return new ArrayList<>();
            else cur = next;
        }
        
        PriorityQueue queue = new PriorityQueue<>((a, b)->(a.count==b.count ? a.word.compareTo(b.word) : b.count-a.count));
        for (Map.Entry entry: cur.counts.entrySet()) {
            queue.offer(new Node(entry.getKey(), entry.getValue()));
        }
        
        List res = new ArrayList<>();
        for (int i = 0; i < 3 && !queue.isEmpty(); i++) {
            res.add(queue.poll().word);
        }
        return res;
    }
}

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/72124.html

相關文章

  • leetcode-211-Add and Search Word - Data structure

    摘要:原題總結棧的利用,先進后出的作用,可以保持鏈表一類的數據的連貫操作,可以用來替代廣度搜索。每一層次可以用進棧出棧進行替代。形式的數據結構,有記憶狀態的作用。應用字符串的遍歷,廣度搜索。 原題: 211. Add and Search Word - Data structure design Design a data structure that supports the follo...

    Alliot 評論0 收藏0
  • [LeetCode] 588. Design In-Memory File System

    Problem Design an in-memory file system to simulate the following functions: ls: Given a path in string format. If it is a file path, return a list that only contains this files name. If it is a direc...

    SHERlocked93 評論0 收藏0
  • [LeetCode] 211. Add and Search Word - Data structu

    Problem Design a data structure that supports the following two operations: void addWord(word)bool search(word)search(word) can search a literal word or a regular expression string containing only let...

    mozillazg 評論0 收藏0
  • leetcode449. Serialize and Deserialize BST

    摘要:題目要求將二叉搜索樹序列化和反序列化,序列化是指將樹用字符串的形式表示,反序列化是指將字符串形式的樹還原成原來的樣子。假如二叉搜索樹的節點較多,該算法將會占用大量的額外空間。 題目要求 Serialization is the process of converting a data structure or object into a sequence of bits so that...

    Honwhy 評論0 收藏0

發表評論

0條評論

MartinHan

|高級講師

TA的文章

閱讀更多
最新活動
閱讀需要支付1元查看
<