Added Graph implementation in C++

trie/Trie.cpp

@@ -0,0 +1,124 @@
+#include <iostream>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+struct node{
+    char data;
+    bool end;
+    node* children[26];
+
+    node(){
+        for(int i=0;i<26;i++){
+            children[i]=NULL;
+        }
+    }
+
+    node(char data){
+        this->data = data;
+        for(int i=0;i<26;i++){
+            children[i]=NULL;
+        }
+    }
+
+    friend ostream& operator<<(ostream& os, const node& n){
+        os<<n.data<<" "<<(n.end?"true":"false")<<" [ ";
+        for(int i=0;i<26;i++){
+            if(n.children[i]!=NULL){
+                os<<char(i+'a')<<", ";
+            }
+        }
+        os<<"\b ]"<<endl;
+        return os;
+    }
+};
+
+class Trie{
+    private:
+        node* root;
+        static void dfs(node* root, string prefix, vector<string> *words){
+            if(root->end){
+                words->push_back(prefix);
+            }
+
+            for(char c='a'; c<='z'; c++){
+                if(root->children[c-'a']!=NULL){
+                    dfs(root->children[c-'a'], prefix+c, words);
+                }
+            }
+        }
+
+    public:
+        Trie(){
+            this->root = new node();
+        }
+
+        void add(string word){
+            node* temp = this->root;
+            for(char c:word){
+                if(temp->children[c-'a']==NULL){
+                    temp->children[c-'a'] = new node(c);
+                }
+                temp = temp->children[c-'a'];
+            }
+            temp->end=true;
+        }
+
+        bool find(string word){
+            node* temp = this->root;
+            for(char c:word){
+                if(temp==NULL){
+                    return false;
+                }
+                temp = temp->children[c-'a'];
+            }
+            if(temp==NULL){
+                return false;
+            }
+            return temp->end;
+        }
+
+        void lookup_node(string word){
+            node* temp = this->root;
+            for(char c:word){
+                if(temp==NULL){
+                    return;
+                }
+                temp = temp->children[c-'a'];
+            }
+            if(temp==NULL){
+                return;
+            }
+            cout<<*temp;
+        }
+
+        vector<string> search(string prefix){
+            node* temp = this->root;
+            vector<string> results;
+            for(char c:prefix){
+                if(temp->children[c-'a']==NULL){
+                    return results;
+                }
+                temp=temp->children[c-'a'];
+            }
+            if(temp==NULL){
+                return results;
+            }
+            dfs(temp, prefix, &results);
+            return results;
+        }
+};
+
+int main(void){
+    Trie t;
+
+    t.add("abc");
+    t.add("abcdef");
+    t.add("def");
+    for(auto w:t.search("ab")){
+        cout<<w<<endl;
+    }
+
+    return 0;
+}