Trie Datastructure

Author: NadigerAmit

Trie/TrieDs.cpp

@@ -0,0 +1,106 @@
+#include<stdio.h>
+#include<iostream>
+#include<string>
+#include<algorithm>
+
+#define CHAR_TO_INT(c) c-'a'
+#define ALPHABET_SIZE 26
+
+using namespace std;
+struct Trie {
+	Trie* childern[ALPHABET_SIZE];
+	bool isleaf;
+};
+
+Trie* getNode() {
+	Trie* pNode = new Trie;
+	
+	std::fill (std::begin(pNode->childern), std::end(pNode->childern), nullptr);
+	
+	pNode->isleaf = false;
+	return pNode;
+}	
+void insert(Trie* pRoot, string str) {
+	if(pRoot == nullptr) {
+		return;
+	}
+	Trie* pCrawl = pRoot;
+	for(auto c:str) {
+		cout<<c <<"" <<CHAR_TO_INT(c) <<" " ;
+		if(pCrawl->childern[CHAR_TO_INT(c)] == nullptr)
+		    pCrawl->childern[CHAR_TO_INT(c)] = getNode();
+		pCrawl = pCrawl->childern[CHAR_TO_INT(c)];
+	}
+	pCrawl->isleaf = true;	
+}
+
+bool search(Trie* pRoot, string str) {
+	if(pRoot == nullptr) {
+		return false;
+	}
+	Trie* pCrawl = pRoot;
+	for(auto c:str) {
+		cout<<c <<"" <<CHAR_TO_INT(c) <<" " ;
+		if(pCrawl->childern[CHAR_TO_INT(c)] == nullptr) {
+			return false;
+		}
+		pCrawl = pCrawl->childern[CHAR_TO_INT(c)];
+	}
+	if(pCrawl->isleaf == false) return false;
+	return true;
+}
+
+bool hasChildern(Trie* pNode) {
+	if(pNode == nullptr) return false;
+	for(auto i =0;i<ALPHABET_SIZE;i++) {
+		if(pNode->childern[i] != nullptr) return true;
+	}
+	return false;
+}
+
+int deleteString(Trie* pRoot, char* c) {
+	if(pRoot == nullptr ) return 0;
+	if(*c){
+		if(pRoot->childern[CHAR_TO_INT(*c)]!=nullptr   // current character is present in the trie
+		    && deleteString(&pRoot[CHAR_TO_INT(*c)],c+1)!=0 // Recurse to next character
+		    && pRoot->isleaf != true) { // is not leaf node
+			    if(!hasChildern(pRoot)) { // this situation is very less likly to happn i.e is not leaf and has no childern 
+					delete pRoot;         // the above can happen whn leaf node is deleted , and left with intermediate nodes in recursive calls 
+					pRoot = nullptr;
+					return 1;
+			    } else {
+					return 0;
+				}
+		}
+	}
+	// here I reached till end of string .
+	if(*c == '\0' && pRoot->isleaf) {
+		if(!hasChildern(pRoot)) {
+			delete pRoot;
+		    pRoot= nullptr;
+		    return 1;
+		} else {
+			pRoot->isleaf = false;
+		}	
+	} 
+	return 0;
+}
+
+// driver program 
+int main() {
+	Trie* root = getNode();
+	cout<<endl;
+	insert(root,"omshreeganeshayanamah");
+	insert(root,"om");
+	insert(root,"omshree");
+	insert(root,"omshreeganesh");
+	cout<<endl;
+	printf("\n Searching\n");
+
+	printf("\nomshreeganeshayanama Is Found = %d\n",search(root,"omshreeganeshayanamah"));
+	printf("\nom Is Found = %d\n",search(root,"om"));
+	printf("\nomshree Is Found = %d\n",search(root,"omshree"));
+	printf("\nomshreegane Is Found = %d\n",search(root,"omshreegane"));
+
+	return 0;
+}