seperate even odd

Author: sachuverma

DSA Crack Sheet/README.md

@@ -156,6 +156,7 @@
 - [Merge K sorted linked lists](https://practice.geeksforgeeks.org/problems/merge-k-sorted-linked-lists/1# "view question") - [Cpp Solution](./solutions/Merge%20K%20sorted%20linked%20lists.cpp)
 - [Multiply two linked lists](https://practice.geeksforgeeks.org/problems/multiply-two-linked-lists/1# "view question") - [Cpp Solution](./solutions/Multiply%20two%20linked%20lists.cpp)
 - [Delete nodes having greater value on right](https://practice.geeksforgeeks.org/problems/delete-nodes-having-greater-value-on-right/1# "view question") - [Cpp Solution](./solutions/Delete%20nodes%20having%20greater%20value%20on%20right.cpp)
+- [Segregate even and odd nodes in a Link List](https://practice.geeksforgeeks.org/problems/segregate-even-and-odd-nodes-in-a-linked-list5035/1 "view question") - [Cpp Solution](./solutions/Segregate%20even%20and%20odd%20nodes%20in%20a%20Link%20List.cpp)
 - []( "view question") - [Cpp Solution](./solutions/.cpp)
 
 ### Binary Tree

DSA Crack Sheet/solutions/Segregate even and odd nodes in a Link List.cpp

@@ -0,0 +1,63 @@
+/*
+Segregate even and odd nodes in a Link List
+============================================
+
+Given a link list of size N, modify the list such that all the even numbers appear before all the odd numbers in the modified list. The order of appearance of numbers within each segregation should be same as that in the original list.
+
+Example 1:
+Input: 
+N = 7
+Link List = 
+17 -> 15 -> 8 -> 9 -> 2 -> 4 -> 6 -> NULL
+Output: 8 2 4 6 17 15 9
+Explaination: 17,15,8,9 are odd so they appear 
+first and 2,4,6 are the even numbers that appear later.
+
+Example 2:
+Input:
+N = 4
+Link List = 1 -> 3 -> 5 -> 7
+Output: 1 3 5 7
+Explaination: There is no even number. 
+So ne need for modification.
+
+Your Task:
+You do not need to read input or print anything. Your task is to complete the function divide() which takes N and head of Link List as input parameters and returns the head of modified link list.
+
+Expected Time Complexity: O(N)
+Expected Auxiliary Space: O(N)
+
+Constraints:
+1 ≤ N ≤ 100
+1 ≤ arr[i] ≤ 10000 
+*/
+
+Node *divide(int N, Node *head)
+{
+  Node *dummy1 = new Node(-1);
+  Node *dummy2 = new Node(-1);
+
+  auto t1 = dummy1, t2 = dummy2;
+  auto t = head;
+
+  while (t)
+  {
+    if (t->data % 2 == 0)
+    {
+      t1->next = t;
+      t = t->next;
+      t1 = t1->next;
+      t1->next = NULL;
+    }
+    else
+    {
+      t2->next = t;
+      t = t->next;
+      t2 = t2->next;
+      t2->next = NULL;
+    }
+  }
+
+  t1->next = dummy2->next;
+  return dummy1->next;
+}