Create Count complete tree nodes

Author: gs146

Count complete tree nodes

@@ -0,0 +1,25 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+class Solution {
+    int cnt=0;
+public:
+    
+    int countNodes(TreeNode* root) {
+        if(root!=NULL)
+        {
+            countNodes(root->left);
+            cnt++;
+            countNodes(root->right);
+        }
+        return cnt;
+    }
+};