Adding Trie data structure div-bargali#298

Adding Trie data structure div-bargali#298

Author: div-bargali

C++/Data-Structures/Trie/Trie.cpp

@@ -0,0 +1,90 @@
+/* 
+
+if the words are : GOAT, GOAL , HELLO, HEY
+then in trie they are stored as
+ Root
+ / \
+ G H
+ / \
+ O E
+ / / \
+ A Y L
+ / \ \
+ T L L
+ \
+ O
+
+
+*/
+#include <string>
+#include <vector>
+#include <map>
+#include <iostream>
+
+struct TrieNode {
+ std::string val;
+ std::map<const char, TrieNode*> Children = {};
+ bool isEnd;
+ TrieNode() { isEnd = false; }
+};
+
+void addToTrie(std::string s, TrieNode* root);
+
+void setupTrie(std::vector<std::string> words, TrieNode* root){
+ for(auto& j : words){
+ addToTrie(j, root);
+ }
+}
+
+void addToTrie(std::string s, TrieNode* root){ 
+ TrieNode* curr = root;
+ 
+ for(int i = 0; i < s.size(); i++){
+ char next = s[i];
+ TrieNode* currNode = curr->Children[next];
+ //if the current node doesn't exist, add it
+ if(!currNode){
+ currNode = new TrieNode();
+ curr->Children[s[i]] = currNode;
+ }
+ curr = currNode;
+ }
+ 
+ curr->isEnd = true;
+}
+
+bool isMember(std::string word, TrieNode* root){
+ TrieNode* curr = root;
+ 
+ for(int i = 0; i < word.length(); i++){
+ const char next = word[i];
+ TrieNode* currNode = curr->Children[next];
+ if(!currNode)
+ return 0;
+ curr = currNode;
+ }
+ return curr->isEnd;
+}
+
+
+//driver
+int main(){
+ std::vector<std::string> words = {"hello", "hi", "yes", "you"};
+ 
+ TrieNode* root = new TrieNode();
+ setupTrie(words, root);
+ std::string s = "hello";
+ std::string s2 = "help";
+ 
+ if(isMember(s,root))
+ std::cout << "hello is a member\n ";
+ else
+ std::cout << "hello not a member\n";
+
+ if(isMember(s2, root))
+ std::cout<<"help is a member\n";
+ else
+ std::cout <<"help is not a member\n";
+ 
+ return 0;
+}