Update repo By Shubhanshu

1]. DSA + CP/1]. DSA/1]. Data Structures/13]. Binary Search Tree/C++/_10)_Delete-Node-in-a-BST.cpp

@@ -0,0 +1,51 @@
+/**
+ * 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:
+
+    //find Inorder Successor
+    TreeNode *getSuccessor(TreeNode *curr){
+        curr = curr->right;
+        while(curr != NULL && curr->left != NULL){
+            curr = curr->left;
+        }
+        return curr;
+    }
+
+    TreeNode* deleteNode(TreeNode* root, int key) {
+
+        if(root == NULL) return NULL;
+
+        if(root->val > key){
+            root->left = deleteNode(root->left,key);
+        }else if(root->val < key){
+            root->right = deleteNode(root->right,key);
+        }else{
+            //node only with one child
+            if(root->left == NULL){
+                TreeNode *temp = root->right;
+                delete(root);
+                return temp;
+            }else if(root->right == NULL){
+                TreeNode *temp = root->left;
+                delete(root);
+                return temp;
+            }else{
+                //Node with both the childs : find Inorder successor
+                TreeNode *succ = getSuccessor(root);
+                root->val = succ->val;
+                root->right = deleteNode(root->right,succ->val);
+            }
+        } 
+        return root;
+    }
+};

1]. DSA + CP/1]. DSA/1]. Data Structures/13]. Binary Search Tree/C++/_11)_Insert-in-BST.cpp

@@ -0,0 +1,64 @@
+/**
+ * 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:
+
+/*<............... Recursive Solution .......................>
+    
+    TreeNode* insertIntoBST(TreeNode* root, int val) {
+                
+        if(root == NULL)
+            return new TreeNode(val);
+        
+        if(root->val > val){
+            root->left = insertIntoBST(root->left,val);
+        }else if(root->val < val){
+            root->right = insertIntoBST(root->right,val);
+        }
+        
+        return root;
+        
+    }
+*/    
+
+//<............... Iterative Solution .......................>
+
+ TreeNode* insertIntoBST(TreeNode* root, int val) {
+
+     TreeNode *temp = new TreeNode(val);
+     TreeNode *curr = root, *parent = NULL;
+
+     while(curr != NULL){
+         parent = curr;
+
+         if(curr->val > val){
+             curr = curr -> left;
+         }else if(curr->val < val){
+             curr = curr -> right;
+         }else{
+             return root;
+         }        
+     }
+
+     if(parent == NULL){
+         return temp;
+     }
+
+     if(parent->val > val){
+         parent->left = temp;
+     }else if(parent->val < val){
+         parent->right = temp;
+     }
+
+     return root;
+    }
+};

1]. DSA + CP/1]. DSA/1]. Data Structures/13]. Binary Search Tree/C++/_12)_LCA-of-a-BST.cpp

@@ -0,0 +1,31 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+
+class Solution {
+public:
+    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
+
+        if(root == NULL)
+            return NULL;
+
+        if(root->val > p->val && root->val > q->val){
+
+            return lowestCommonAncestor(root->left,p,q);
+
+        }else if(root->val < p->val && root->val < q->val){
+
+            return lowestCommonAncestor(root->right,p,q);
+
+        }
+
+        return root;
+    }
+
+};

1]. DSA + CP/1]. DSA/1]. Data Structures/13]. Binary Search Tree/C++/_13)_Search-in-BST.cpp

@@ -0,0 +1,51 @@
+/**
+ * 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:
+
+// <................> Approach - 01 <................>(Recurisive Approach)  
+/*  
+
+    TreeNode* searchBST(TreeNode* root, int val) {
+            
+        if(root == NULL) return {};
+        
+        if(root->val == val) return root;
+        
+        if(root->val > val){
+            return searchBST(root->left,val);
+        }else{
+            return searchBST(root->right,val);
+        } 
+    }  
+    
+*/    
+
+// <................> Approach - 02 <................>(Iterative Approach)
+
+  TreeNode* searchBST(TreeNode* root, int val) {
+
+        while(root!=NULL){
+
+            if(root -> val == val){
+                return root;
+            }else if(root->val > val){
+                root = root->left;
+            }else{
+                root = root->right;
+            }
+        }
+
+        return {};
+
+    }
+};