Create main.cpp

Author: JawadSher

21 - Trie Data Structure Problems/01 - Example/main.cpp

@@ -0,0 +1,117 @@
+#include <iostream>
+using namespace std;
+
+class TrieNode{
+  public:
+    char data;
+    TrieNode* children[26];
+    bool isTerminal;
+
+    TrieNode(int data){
+      this -> data = data;
+      for(int i = 0; i < 26; i++) children[i] = NULL;
+      isTerminal = false;
+    }
+};
+
+class Trie{
+  public:
+    TrieNode* root;
+
+    Trie(){
+      root = new TrieNode('\0');
+    }
+
+    void insertUtil(TrieNode* root, string& word, int index){
+      if(index == word.size()) {
+        root -> isTerminal = true;
+        return;
+      }
+
+      int charIndex = word[index] - 'a';
+      if(root -> children[charIndex] == NULL) root -> children[charIndex] = new TrieNode(word[index]);
+      
+      insertUtil(root->children[charIndex], word, index+1);
+    }
+    void insertWord(string word){
+      for (char& c : word) c = tolower(c);
+      insertUtil(root, word, 0);
+    }
+    
+    bool searchUtil(TrieNode* root, string word, int index){
+      if(index == word.size()) return root -> isTerminal;
+
+      int charIndex = word[index] - 'a';
+      if(root -> children[charIndex] == NULL) return false;
+
+      return searchUtil(root->children[charIndex], word, index+1);
+    }
+
+    bool searchWord(string word){
+      for (char& c : word) c = tolower(c);
+      return searchUtil(root, word, 0);
+    }
+
+    bool removeWordUtil(TrieNode* root, string word, int index){
+      if(index == word.size()){
+        if(!root -> isTerminal) return false;
+        
+        root -> isTerminal = false;
+
+        for(int i = 0; i < 26; i++) if(root -> children[i] != NULL) return false;
+        return true;
+      } 
+
+      int charIndex = word[index] - 'a';
+      TrieNode* child = root -> children[charIndex];
+      if(child == NULL) return false;
+
+      bool shouldDeleteChild = removeWordUtil(child, word, index + 1);
+
+      if(shouldDeleteChild){
+        delete child;
+        root -> children[charIndex] = NULL;
+
+        if(!root -> isTerminal){
+          for(int i = 0; i < 26; i++) if(root->children[i] != NULL) return false;
+          return true;
+        }
+      }
+
+      return false;
+    }
+    void removeWord(string word){
+      for (char& c : word) c = tolower(c);
+      removeWordUtil(root, word, 0);
+    }
+};
+
+int main() {
+  Trie* t = new Trie();
+
+  // Insert words
+  t->insertWord("abcd");
+  t->insertWord("abc");
+  t->insertWord("trie");
+
+
+  // Search words
+  cout << "------------- Search Words -------------" << endl;
+  cout << "abc : "<<(t->searchWord("abc") ? "Found\n" : "Not Found\n");
+  cout << "abcd : "<<(t->searchWord("abcd") ? "Found\n" : "Not Found\n");
+  cout << "trie : "<<(t->searchWord("trie") ? "Found\n" : "Not Found\n");
+  cout << "tried : "<<(t->searchWord("tried") ? "Found\n" : "Not Found\n");
+
+  // Remove words
+  cout << "------------- Remove Words -------------" << endl;
+  t->removeWord("abc");
+  t->removeWord("abcd");
+
+  cout << "abc : "<<(t->searchWord("abc") ? "Found\n" : "Not Found\n");
+  cout << "abcd : "<<(t->searchWord("abcd") ? "Found\n" : "Not Found\n");
+
+  // Cleanup
+  delete t; 
+  
+  return 0;
+}