Merge pull request #5 from Chayandas07/Chayandas07-patch-5

Create 30 November  Reorder List

Author: Chayandas07

30 November Reorder List

@@ -0,0 +1,44 @@
+class Solution{ 
+public:
+    Node* reverse(Node* head)
+{
+    Node* curr = head;
+    Node *next = NULL, *prev = NULL;
+    while(curr)
+    {
+        next = curr->next;
+        curr->next = prev;
+        prev = curr;
+        curr = next;
+    }
+    return prev;
+}
+Node* merge(Node* a,Node* b)
+{
+    while(b)
+    {
+        Node* temp1=a->next;
+        Node* temp2=b->next;
+        
+        a->next=b;
+        b->next=temp1;
+        a=temp1;
+        b=temp2;
+    }
+    return a;
+}
+void reorderList(Node* head) 
+{
+    if(!head || !head->next) return;
+    Node *slow = head;
+    Node *fast = head->next;
+    while(fast&&fast->next)
+        {
+            slow=slow->next;
+            fast=fast->next->next;
+        }
+    Node* shead = reverse(slow->next);
+    slow->next=NULL;
+    merge(head,shead);
+}
+};