Create Populating Next Right Pointers in Each Node.cpp

Author: daizhenyang

Populating Next Right Pointers in Each Node.cpp

@@ -0,0 +1,47 @@
+/**
+ * Definition for binary tree with next pointer.
+ * struct TreeLinkNode {
+ *  int val;
+ *  TreeLinkNode *left, *right, *next;
+ *  TreeLinkNode(int x) : val(x), left(NULL), right(NULL), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    void connect(TreeLinkNode *root) {
+        // Start typing your C/C++ solution below
+        // DO NOT write int main() function
+        if (!root)return;
+        queue<TreeLinkNode *>q;
+        q.push(root);
+        int node_in_now_level=1;
+        int node_in_next_level=0;
+        TreeLinkNode *last=NULL;
+        while (!q.empty())
+        {
+            TreeLinkNode *t=q.front();
+            q.pop();
+            if (last)last->next=t;
+            node_in_now_level--;
+            if (t->left)
+            {
+                node_in_next_level++;
+                q.push(t->left);
+            }
+            if (t->right)
+            {
+                node_in_next_level++;
+                q.push(t->right);
+            }
+            if (!node_in_now_level)
+            {
+                last=NULL;
+                swap(node_in_now_level,node_in_next_level);
+            }
+            else 
+            {
+                last=t;
+            }
+        }
+    }
+};