Create Copy_List_With_Random_Pointer.cc

Author: iphkwan

Copy_List_With_Random_Pointer.cc

@@ -0,0 +1,40 @@
+/**
+ * Definition for singly-linked list with a random pointer.
+ * struct RandomListNode {
+ *     int label;
+ *     RandomListNode *next, *random;
+ *     RandomListNode(int x) : label(x), next(NULL), random(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    RandomListNode *copyRandomList(RandomListNode *head) {
+        // Note: The Solution object is instantiated only once and is reused by each test case.
+        RandomListNode *ret = NULL, *tmp = head, *entry = NULL;
+        RandomListNode **pCur = &ret;
+        while (tmp) {
+            entry = tmp;
+            tmp = tmp->next;
+            entry->next = new RandomListNode(entry->label);
+            entry->next->next = tmp;
+        }
+        
+        tmp = head;
+        while (tmp) {
+            entry = tmp->next;
+            if (tmp->random)
+                entry->random = tmp->random->next;
+            tmp = entry->next;
+        }
+        
+        tmp = head;
+        while (tmp) {
+            entry = tmp->next;
+            *pCur = entry;
+            tmp->next = entry->next;
+            tmp = tmp->next;
+            pCur = &((*pCur)->next);
+        }
+        return ret;
+    }
+};