learn linkedlist

linkedlist.cpp

@@ -0,0 +1,159 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+struct Node {
+    int data;
+    Node *next;
+    Node(int x) {
+        this->data = x;
+        this->next = NULL;
+    }
+};
+
+Node *insertBeforeHead(Node *head, int x) {
+    Node *newNode = new Node(x);
+    newNode->next = head;
+    return newNode;
+}
+//2x 3y 4null
+//2x 5t 3y 4null
+void insertAfterHead(Node *head, int x) {
+    if(head==NULL)
+        return;
+    Node *newNode = new Node(x);
+    Node *temp = head->next;
+    head->next = newNode;
+    newNode->next = temp;
+}
+
+void print(Node *head) {
+    Node *curr = head;
+    while(curr!=NULL) {
+        cout << curr->data << " ";
+        curr = curr->next;
+    }
+    cout << endl;
+}
+
+Node* insertAtEnd(Node *head, int x) {
+
+    Node *newNode = new Node(x);
+
+    if(head==NULL) {
+       return newNode; 
+    }
+
+    Node *temp = head;
+
+    while(temp->next!=NULL) {
+        temp = temp->next;
+    }
+    temp->next = newNode;
+    return head;
+}
+
+
+//1x 3b 4h 10i 7null 8
+void insertAfterNode(Node* head, int x, int y) {
+    Node* temp = head;
+    while(temp!=NULL) {
+        if(temp->data==x) {
+            Node *newNode = new Node(y);
+            Node *curr = temp->next;
+            temp->next = newNode;
+            newNode->next = curr;
+            break;
+        }
+        else {
+            temp = temp->next;
+        }         
+    }
+}
+
+//1y 3y 5u 5
+bool searchNumber(Node *head, int x) {
+    Node *temp = head;
+    while(temp!=NULL) {
+        if(temp->data==x)
+            return true;
+        else
+            temp = temp->next;
+    }
+    return false;
+}
+
+Node* deleteHead(Node* head) {
+    if(head==NULL)
+        return NULL;
+
+    Node* temp = head->next;
+    delete head;
+    return temp;
+}
+
+//1t 3y 5null 5
+//1t 3y 5x 8n 9null
+Node* deleteGivenNode(Node* head, int x) {
+    if(head==NULL)
+        return NULL;
+    else if(head->data==x) {
+        Node* temp = head->next;
+        delete head;
+        return temp;
+    }
+    else {
+        Node* curr=head;
+        while(curr->next!=NULL) {
+            if(curr->next->data==x) {
+                Node* temp = curr->next;
+                curr->next = curr->next->next;
+                delete temp;
+                return head;
+            }
+            else 
+                curr = curr->next;
+
+        }
+        return head;
+    }
+
+}
+
+//1z 3t 6y 8u 9null
+//9y 8t 6z 3head 1null
+
+Node* reverseLinkedlist(Node* head) {
+
+    vector <int> numbers;
+    Node* temp = head;
+    while(temp!=NULL) {
+        numbers.push_back(temp->data);
+        temp = temp->next;
+    }
+    int count = numbers.size();
+    Node* curr = head;
+    for(int i=count-1; i>=0; i--) {
+        curr->data = numbers[i];
+        curr = curr->next;
+    }
+    return head;
+}
+
+
+
+
+int main() {
+    Node *head = new Node(5);
+    insertAfterHead(head,6);
+    insertAfterHead(head,0);
+    head = insertBeforeHead(head,1);
+    head = insertAtEnd(head,123);
+    print(head);
+    head = deleteGivenNode(head,123);
+    print(head);
+    head = reverseLinkedlist(head);
+    print(head);
+
+}
+
+