add remove_nth_node_from_end_of_list.cpp

Author: jakoo

remove_nth_node_from_end_of_list.cpp

@@ -0,0 +1,31 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode* removeNthFromEnd(ListNode* head, int n) {
+        ListNode* front = head;
+        ListNode* behind = head;
+        ListNode* behind2 = NULL;
+        for (int i = 0; i < n; ++i)
+            front = front->next;
+            
+        while (front != NULL)
+        {
+            front = front->next;
+            behind2 = behind;
+            behind = behind->next;
+        }
+            
+        if (behind2 == NULL) // head will be deleted
+            return behind->next;
+        
+        behind2->next = behind->next;
+        return head;
+    }
+};