Create 0117-populating-next-right-pointers-in-each-node-ii.cpp

Author: Abe0770

Diff for: cpp/0117-populating-next-right-pointers-in-each-node-ii.cpp

@@ -0,0 +1,68 @@
+/*
+  Given a binary tree
+
+  struct Node {
+    int val;
+    Node *left;
+    Node *right;
+    Node *next;
+  }
+  
+  Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL.
+  
+  Initially, all next pointers are set to NULL.
+
+  Ex. Input: root = [1,2,3,4,5,null,7]
+      Output: [1,#,2,3,#,4,5,7,#]
+      Explanation: Given the above binary tree (Figure A), your function should populate each next pointer to point to its next right node,
+      just like in Figure B. The serialized output is in level order as connected by the next pointers, with '#' signifying the end of each level.
+
+  Time  : O(N)
+  Space : O(1)
+*/
+
+/*
+// Definition for a Node.
+class Node {
+public:
+    int val;
+    Node* left;
+    Node* right;
+    Node* next;
+
+    Node() : val(0), left(NULL), right(NULL), next(NULL) {}
+
+    Node(int _val) : val(_val), left(NULL), right(NULL), next(NULL) {}
+
+    Node(int _val, Node* _left, Node* _right, Node* _next)
+        : val(_val), left(_left), right(_right), next(_next) {}
+};
+*/
+
+class Solution {
+public:
+    Node* connect(Node* root) {
+        if(root == NULL)
+            return NULL;
+        Node* parent = root;
+
+        while(parent) {
+            Node* newNode = new Node;
+            Node* temp = newNode;
+
+            while(parent) {
+                if(parent -> left) {
+                    temp -> next = parent -> left;
+                    temp = temp -> next;
+                }
+                if(parent -> right) {
+                    temp -> next = parent -> right;
+                    temp = temp -> next;
+                }
+                parent = parent -> next;
+            }
+            parent = newNode -> next;
+        }
+        return root;
+    }
+};