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Author: ZWiley

copy-list-with-random-pointer.cpp

@@ -0,0 +1,31 @@
+// A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.
+// Return a deep copy of the list. 
+/**
+ * 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) {
+            RandomListNode *copy,*p;
+            if (!head) return NULL;
+            for(p=head;p;p=p->next){
+                copy = new RandomListNode(p->label);
+                copy->next = p->next; // insert new at old next
+                p = p->next = copy;
+            }
+            for(p=head;p;p=copy->next){
+                copy = p->next;          // copy random point
+                copy->random = (p->random?p->random->next:NULL);
+            }
+            for(p=head,head=copy=p->next;p;){
+                p = p->next = copy->next; // split list
+                copy = copy->next = (p?p->next:NULL);
+            }
+            return head;
+        }
+};