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| − | '''C'''
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| − | <pre>
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| − | typedef struct Node {
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| − | char *value;
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| − | struct Node *next;
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| − | } Node;
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| | | | |
| − | int reverse(Node **head) {
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| − | Node *curr, *prev, *next;
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| − |
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| − | if (!head || !(*head)) {
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| − | return 0;
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| − | }
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| − |
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| − | curr = *head;
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| − | prev = NULL;
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| − | next = NULL;
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| − |
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| − | while (curr) {
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| − | next = curr->next;
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| − | curr->next = prev;
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| − | prev = curr;
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| − | curr = next;
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| − | }
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| − |
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| − | *head = prev;
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| − |
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| − | return 1;
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| − | }
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| − | </pre>
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| − | ----
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| − | '''Dart'''
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| − | <pre>
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| − | class Node<T> {
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| − | Node(this.value, [this.next]);
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| − | T value;
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| − | Node next;
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| − | @override String toString() => '$value $next';
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| − | }
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| − |
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| − | Node reverse(Node n) {
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| − | Node curr = n.next;
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| − | n.next = null; // `n` is the new tail.
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| − | while(curr != null) {
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| − | Node tmp = curr.next; // Start swap.
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| − | curr.next = n; // next => previous
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| − | n = curr; // Update loop's previous node.
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| − | curr = tmp; // Update loop's current node.
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| − | }
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| − | return n;
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| − | }
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| − |
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| − | // Example
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| − | void main() {
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| − | final list = Node(1, Node(2, Node(3, Node(4, Node(5)))));
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| − | print(list); // 1 2 3 4 5 null
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| − | print(reverse(list)); // 5 4 3 2 1 null
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| − | }
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| − | </pre>
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| − | ----
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| − |
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| − | '''In Java
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| − | '''
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| − | <pre>
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| − | class ListNode {
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| − | int val;
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| − | ListNode next;
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| − |
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| − | ListNode(final int x) {
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| − | val = x;
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| − | next = null;
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| − | }
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| − | }
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| − |
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| − | public class LinkedList {
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| − | ListNode head;
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| − |
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| − | public LinkedList() {
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| − | head = null;
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| − | }
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| − |
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| − | public void prepend(final int in) {
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| − | final ListNode data = new ListNode(in);
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| − | data.next = head;
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| − | head = data;
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| − | }
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| − |
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| − | public void appendToList(final int in) {
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| − | final ListNode data = new ListNode(in);
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| − | ListNode current = head;
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| − | if (head == null) {
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| − | head = data;
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| − | return;
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| − | }
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| − | while (current.next != null) {
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| − | current = current.next;
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| − | }
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| − | current.next = data;
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| − | }
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| − |
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| − | public void printList(final ListNode head) {
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| − | ListNode current = head;
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| − | while (current != null) {
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| − | System.out.print(current.val + " -> ");
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| − | current = current.next;
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| − | }
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| − | System.out.println();
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| − | }
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| − |
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| − | public ListNode reverseList(final ListNode node) {
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| − | //what if 0 node in list
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| − | if (node == null) {
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| − | return null;
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| − | }
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| − | //what if 1 node in list
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| − | if (node.next == null) {
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| − | return node;
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| − | }
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| − | //what if multiple nodes.divide into two parts . reverse second part recursively and in end point second.next to first
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| − | final ListNode secondElem = node.next;
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| − | node.next = null;
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| − | final ListNode reverseRest = reverseList(secondElem);
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| − | secondElem.next = node;
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| − | return reverseRest;
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| − | }
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| − |
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| − | public static void main(final String[] args) {
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| − | final LinkedList linkedList = new LinkedList();
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| − | linkedList.appendToList(12);
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| − | linkedList.appendToList(13);
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| − | linkedList.appendToList(14);
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| − | linkedList.appendToList(15);
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| − | linkedList.printList(linkedList.head);
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| − | final ListNode head = linkedList.reverseList(linkedList.head);
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| − | linkedList.printList(head);
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| − | }
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| − |
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| − | }
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| − | </pre>
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| − |
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| − | ----
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| − | '''In Python
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| − | '''
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| − | <pre>
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| − |
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| − | class Node():
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| − | def __init__(self, value):
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| − | self.value = value
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| − | self.next = None
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| − |
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| − | class LinkedList():
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| − | def __init__(self):
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| − | self.head = None
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| − | self.tail = None
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| − |
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| − | def add_node(self, value):
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| − | if not self.head:
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| − | self.__initialize_list(value)
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| − | else:
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| − | node = Node(value)
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| − | self.tail.next = node
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| − | self.tail = node
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| − |
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| − | def print_list(self):
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| − | current_node = self.head
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| − |
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| − | print('head ->'),
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| − | while current_node is not None:
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| − | print(current_node.value),
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| − |
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| − | current_node = current_node.next
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| − |
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| − | print('->'),
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| − |
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| − | print('tail')
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| − |
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| − | def reverse(self):
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| − | current_head = self.head
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| − | head = self.head
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| − |
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| − | while current_head is not None:
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| − | temp = current_head
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| − | current_head = head.next
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| − | t_next = current_head.next
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| − | head.next = t_next
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| − | current_head.next = temp
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| − |
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| − | if head.next is None:
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| − | self.head = current_head
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| − | break
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| − |
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| − | def __initialize_list(self, value):
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| − | self.head = Node(value)
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| − | self.tail = self.head
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| − | </pre>
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| − |
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| − |
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| − | ----
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| − |
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| − | [[Data-structures-TADM2E|Back to ''Data Structures'' Problems]]...
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