added ll_palindrome.cpp

Author: sumeyyadede

ll_palindrome.cpp

@@ -0,0 +1,114 @@
+#include <iostream>
+#include <map>
+
+using namespace std; 
+
+class Node{
+public:
+	Node(){
+		next = NULL;
+	}
+	//void setValue(int value){
+	//	data = value;
+	//}
+	//int getValue(){
+	//	return data;
+	//}
+//private:
+	int data;
+	Node* next;
+};
+
+class LinkedList{
+public:
+	LinkedList(){
+		head = NULL;
+	}
+	void printAll();
+	void insert_head(int);
+	void insert_front(int);
+	void setHead(Node*);
+	Node* getHead();
+
+private:
+	Node* head;
+
+};
+
+void LinkedList::setHead(Node* node){
+	this->head = node;
+}
+Node* LinkedList::getHead(){
+	return this->head;
+}
+void LinkedList::insert_head(int value){
+	Node* node = new Node;
+	node->data = value;
+	node->next = head;
+	head = node;
+}
+void LinkedList::insert_front(int value){
+	Node* node = new Node;
+	if(head == NULL){
+		head = node;
+	}
+	else{
+		Node* iter = head;
+		while(iter->next != NULL){
+			iter = iter->next;
+		}
+		iter->next = node;
+	}
+	node->data = value;
+	node->next = NULL;
+}
+void LinkedList::printAll(){
+	Node* p;
+	p = head;
+	while(p != NULL){
+		cout << p->data << endl;
+		p = p->next;
+	}
+	cout << "-----" << endl;
+}
+
+bool is_palindrome_ll(LinkedList* l1){
+	Node* node = l1->getHead();
+	int len = 0;
+	map<int, int> ht;
+	
+	while(node != NULL){
+		ht[node->data] = ht[node->data] + 1;
+		node = node->next;
+		len += 1;
+	}
+	int has_visit_odd = len % 2 == 0 ? 1 : 0;
+
+	for(int i=0; i<ht.size(); i++){
+		if(ht[i] % 2 == 1){
+			if(has_visit_odd == 1){
+				return false;
+			}
+			else{
+				has_visit_odd = 1;
+			}
+		}	
+	}
+	return true;
+}
+
+int main(){
+
+	LinkedList* l1 = new LinkedList;
+	l1->insert_front(2);
+	l1->insert_front(3);
+	l1->insert_front(5);
+	l1->insert_front(5); 
+	l1->insert_front(3);
+	l1->insert_front(2);
+	l1->printAll();
+	cout << is_palindrome_ll(l1) << endl;
+
+	return 0;
+}
+