Adding recusrsive approach to "21. Merge Two Sorted Lists"

kunaldawn · Oct 7, 2019 · 58a77bd · 58a77bd
1 parent 90bb2aa
commit 58a77bd
Showing 1 changed file with 16 additions and 0 deletions.
diff --git a/leetcode/src/21.c b/leetcode/src/21.c
@@ -1,3 +1,4 @@
+/* Iterative approach */
 struct ListNode* mergeTwoLists(struct ListNode* l1, struct ListNode* l2) {
     struct ListNode *list = NULL;
     struct ListNode *tmp = NULL;
@@ -38,3 +39,18 @@ struct ListNode* mergeTwoLists(struct ListNode* l1, struct ListNode* l2) {
     return NULL;
 }
 
+
+/* Recursive approach */
+struct ListNode* mergeTwoLists(struct ListNode* l1, struct ListNode* l2) {
+    if(!l1)
+        return l2;t 
+        return l1;
+    if(l1->val < l2->val) {
+        l1->next = mergeTwoLists(l1->next, l2);
+        return l1;
+    } else {
+        l2->next = mergeTwoLists(l1, l2->next);
+        return l2;
+    }
+}
+