Create main.cpp

Author: JawadSher

18 - Binary Search Tree Data Structure Problems/07 - K-th Smallest Element in BST/main.cpp

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+class Solution {
+  public:
+    // Return the Kth smallest element in the given BST
+    int KthSmallestElement(Node *root, int k) {
+        Node* current = root;
+        int count = 0;
+        int element = -1;
+        
+        while(current != NULL){
+            if(current -> left == NULL){
+                count++;
+                if(count == k) element = current -> data;
+                current = current -> right;
+            }else{
+                Node* predecessor = current -> left;
+                while(predecessor -> right != NULL && predecessor -> right != current){
+                    predecessor = predecessor -> right;
+                }
+                
+                if(predecessor -> right == NULL){
+                    predecessor -> right = current;
+                    current = current -> left;
+                }else{
+                    predecessor -> right = NULL;
+                    count++;
+                    if(count == k) element = current -> data;
+                    current = current -> right;
+                }
+            }
+            if(element != -1) break;
+        }
+        
+        
+        return element;
+    }
+};