rotate LL

Author: sachuverma

Striver Sheet/Day-6/Rotate List.cpp

@@ -0,0 +1,69 @@
+/*
+Rotate List
+===========
+
+Given the head of a linked list, rotate the list to the right by k places.
+
+Example 1:
+Input: head = [1,2,3,4,5], k = 2
+Output: [4,5,1,2,3]
+
+Example 2:
+Input: head = [0,1,2], k = 4
+Output: [2,0,1]
+
+Constraints:
+The number of nodes in the list is in the range [0, 500].
+-100 <= Node.val <= 100
+0 <= k <= 2 * 109
+*/
+
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode() : val(0), next(nullptr) {}
+ *     ListNode(int x) : val(x), next(nullptr) {}
+ *     ListNode(int x, ListNode *next) : val(x), next(next) {}
+ * };
+ */
+class Solution
+{
+public:
+  ListNode *rotateRight(ListNode *head, int k)
+  {
+    if (!head || !head->next)
+      return head;
+
+    auto tail = head;
+    int size = 0;
+    auto temp = head;
+    while (temp)
+    {
+      size++;
+      temp = temp->next;
+      if (tail->next)
+        tail = tail->next;
+    }
+
+    k = k % size;
+
+    if (!k)
+      return head;
+
+    ListNode *dummy = new ListNode(-1);
+    dummy->next = head;
+    temp = dummy;
+
+    for (int i = 0; i < size - k; ++i)
+    {
+      temp = temp->next;
+    }
+
+    head = temp->next;
+    temp->next = NULL;
+    tail->next = dummy->next;
+    return head;
+  }
+};

Striver Sheet/README.md

@@ -55,7 +55,7 @@
 - [Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list/) - [Cpp Soultion](./Day-6/Palindrome%20Linked%20List.cpp)
 - [Linked List Cycle II](https://leetcode.com/problems/linked-list-cycle-ii/) - [Cpp Soultion](./Day-6/Linked%20List%20Cycle%20II.cpp)
 - [Flattening a Linked List](https://practice.geeksforgeeks.org/problems/flattening-a-linked-list/1#) - [Cpp Soultion](./Day-6/Flattening%20a%20Linked%20List.cpp)
-- []() - [Cpp Soultion](./Day-6/.cpp)
+- [Rotate List](https://leetcode.com/problems/rotate-list/) - [Cpp Soultion](./Day-6/Rotate%20List.cpp)
 
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