648. Replace Words

class TrieNode {
public:
    TrieNode* children[26];
    bool isEndOfWord;
    TrieNode() {
        isEndOfWord = false;
        for (int i = 0; i < 26; ++i) {
            children[i] = nullptr;
        }
    }
};

class Trie {
public:
    TrieNode* root;
    Trie() {
        root = new TrieNode();
    }

    void insert(string word) {
        TrieNode* curr = root;
        for (char c : word) {
            int index = c - 'a';
            if (!curr->children[index]) {
                curr->children[index] = new TrieNode();
            }
            curr = curr->children[index];
        }
        curr->isEndOfWord = true;
    }

    bool search(string word) {
        TrieNode* curr = root;
        for (char c : word) {
            int index = c - 'a';
            if (!curr->children[index]) {
                return false;
            }
            curr = curr->children[index];
        }
        return curr->isEndOfWord;
    }

    bool startsWith(string prefix) {
        TrieNode* curr = root;
        for (char c : prefix) {
            int index = c - 'a';
            if (!curr->children[index]) {
                return false;
            }
            curr = curr->children[index];
        }
        return true;
    }

    string findShortedPrefix(string word) {
        TrieNode* curr = root;
        for (int i = 0; i < word.length(); ++i) {
            int index = word[i] - 'a';
            if (!curr->children[index]) {
                return word;
            }
            curr = curr->children[index];
            if (curr->isEndOfWord) {
                return word.substr(0, i + 1);
            }
        }
        return word;
    }
};

class Solution {
public:
    string replaceWords(vector<string>& dictionary, string sentence) {
        Trie trie;
        for (string& word : dictionary) {
            trie.insert(word);
        }
        vector<string> tokens;
        string token;
        for (char c : sentence) {
            if (c == ' ') {
                tokens.push_back(token);
                token = "";
            } else {
                token += c;
            }
        }
        tokens.push_back(token);
        string result = "";
        for (string& token : tokens) {
            string prefix = trie.findShortedPrefix(token);
            result += prefix + " ";
        }
        result.pop_back(); // Remove trailing space
        return result;
    }
};