added linkedlist section

Linked List/328 odd even Linked List/328.odd-even-linked-list.cpp

+/*
+ * @lc app=leetcode id=328 lang=cpp
+ *
+ * [328] Odd Even Linked List
+ */
+
+// @lc code=start
+/**
+ * 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 *oddEvenList(ListNode *head)
+    {
+        if (!head || !head->next)
+        {
+            return head;
+        }
+
+        ListNode dummy;
+        ListNode *dummyPtr = &dummy;
+        ListNode *curr = head->next;
+        ListNode *prev = head;
+        int cnt = 0;
+        while (curr)
+        {
+            if (cnt % 2 == 0)
+            {
+                prev->next = curr->next;
+                dummyPtr->next = curr;
+                curr = curr->next;
+                dummyPtr = dummyPtr->next;
+                dummyPtr->next = nullptr;
+            }
+            else
+            {
+                prev = prev->next;
+                curr = curr->next;
+            }
+            cnt++;
+        }
+
+        prev->next = dummy.next;
+        return head;
+    }
+};
+// @lc code=end

Linked List/328 odd even Linked List/Readme.md

+# 328 Odd Even Linked List
+