Create iterative_inorder_traversal.cpp

iterative_inorder_traversal.cpp

@@ -0,0 +1,46 @@
+/**
+ * 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 {
+public:
+    vector<int> inorderTraversal(TreeNode* root) {
+
+        // iterative approach
+        stack<TreeNode*>s;
+        vector<int>ans;
+
+        TreeNode * cur = root;
+
+        if(root==NULL)
+            return ans;
+
+        while(!s.empty() || cur!=NULL)
+        {
+            while(cur!=NULL)
+            {
+                s.push(cur);
+                cur = cur->left;
+            }
+
+            cur = s.top();
+            ans.push_back(cur->val);
+            s.pop();
+
+            cur = cur->right;
+
+        }
+        return ans;
+
+
+
+
+    }
+};