Create main.cpp

Author: JawadSher

18 - Binary Search Tree Data Structure Problems/06 - Kth Smallest Element in a BST/main.cpp

@@ -0,0 +1,32 @@
+/**
+ * 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:
+    int solve(TreeNode* root, int &i, int k){
+        if(root == NULL) return -1;
+
+        int left = solve(root -> left, i, k);
+        if(left != -1) return left;
+
+        i++;
+        if(i == k) return root -> val;
+
+        return solve(root -> right, i, k);
+    }
+    int kthSmallest(TreeNode* root, int k) {
+
+        int i = 0;
+        int ans = solve(root, i, k);
+
+        return ans;
+    }
+};