Create 369.Plus-One-Linked-List.cpp

Author: wisdompeak

Linked_List/369.Plus-One-Linked-List/369.Plus-One-Linked-List.cpp

@@ -0,0 +1,43 @@
+/**
+ * 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* plusOne(ListNode* head) 
+    {
+        int carry = 0;
+        dfs(head, carry);
+        if (carry == 0)
+            return head;
+        else
+        {
+            ListNode* node = new ListNode(1);
+            node->next = head;
+            return node;
+        }
+    }
+    
+    void dfs(ListNode* head, int& carry) 
+    {       
+        if (head==NULL)
+        {
+            carry = 1;
+            return;
+        }
+        
+        dfs(head->next, carry);
+        
+        int val = head->val + carry;
+        carry = val / 10;
+        head->val = val % 10;        
+        
+        // if (head->val==3) cout<<val<<endl;
+    }
+};