🐎 Day 20

Author: AkashRajpurohit

README.md

@@ -28,6 +28,7 @@
 3. [Distribute Candies to People](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/550/week-2-august-8th-august-14th/3427/) ➡️ [CPP Solution](Week3/distributeCandies.cpp)
 4. [Numbers With Same Consecutive Differences](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/550/week-2-august-8th-august-14th/3428/) ➡️ [CPP Solution](Week3/numsSameConsecDiff.cpp)
 5. [Goat Latin](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/550/week-2-august-8th-august-14th/3429/) ➡️ [CPP Solution](Week3/toGoatLatin.cpp) [JS Solution](Week3/toGoatLatin.js)
+6. [Reorder List](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/550/week-2-august-8th-august-14th/3430/) ➡️ [CPP Solution](Week3/reorderList.cpp)
 
 ## Week 4 🚧
 Coming Soon...

Week3/reorderList.cpp

@@ -0,0 +1,67 @@
+/**
+ * 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 {
+    void reverseList(ListNode** head) {
+        ListNode* next;
+        ListNode* prev = NULL;
+        ListNode* curr = *head;
+        
+        while (curr) { 
+            next = curr->next; 
+            curr->next = prev; 
+            prev = curr; 
+            curr = next; 
+        } 
+
+        *head = prev;
+    }
+public:
+    void reorderList(ListNode* head) {
+        if(head == NULL) return;
+        
+        ListNode* fast = head->next;
+        ListNode* slow = head;
+        
+        while(fast && fast->next) {
+            fast = fast->next->next;
+            slow = slow->next;
+        }
+        
+        ListNode* head1 = head;
+        ListNode* head2 = slow->next;
+        
+        slow->next = NULL;
+        
+        reverseList(&head2);
+        
+        head = new ListNode(0);
+        
+        ListNode* curr = head;
+        
+        while(head1 || head2) {
+            
+            if(head1) {
+                curr->next = head1;
+                curr = curr->next;
+                head1 = head1->next;
+            }
+            
+            if(head2) {
+                curr->next = head2;
+                curr = curr->next;
+                head2 = head2->next;
+            }
+            
+        }
+        
+        head = head->next;
+    }
+};