Create 648. Replace Words (#497)

Author: Chayandas07

648. Replace Words

@@ -0,0 +1,98 @@
+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;
+    }
+};