vault backup: 2022-07-07 08:16:24

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CS notes/pages/Leetcode Binary-Tree-Inorder-Traversal.md

@@ -20,7 +20,10 @@ tag:#DFS
  
 - [[Leetcode Binary-Tree-Postorder-Traversal]]
 - [[Leetcode Binary-Tree-Preorder-Traversal]]
+- [[Leetcode Invert-Binary-Tree]]
 - [[Leetcode Maximum-Depth-Of-Binary-Tree]]
+- [[Leetcode Path-Sum]]
+- [[Leetcode Search-In-a-Binary-Tree]]
 - [[Leetcode Symmetric-Tree]]
  
 

CS notes/pages/Leetcode Binary-Tree-Level-Order-Traversal.md

@@ -19,6 +19,7 @@ tag:#BFS
 ```
  
 - [[Leetcode Maximum-Depth-Of-Binary-Tree]]
+- [[Leetcode Search-In-a-Binary-Tree]]
  
 
 ##### Links:

CS notes/pages/Leetcode Binary-Tree-Postorder-Traversal.md

@@ -20,7 +20,10 @@ tag:#DFS
  
 - [[Leetcode Binary-Tree-Inorder-Traversal]]
 - [[Leetcode Binary-Tree-Preorder-Traversal]]
+- [[Leetcode Invert-Binary-Tree]]
 - [[Leetcode Maximum-Depth-Of-Binary-Tree]]
+- [[Leetcode Path-Sum]]
+- [[Leetcode Search-In-a-Binary-Tree]]
 - [[Leetcode Symmetric-Tree]]
  
 

CS notes/pages/Leetcode Binary-Tree-Preorder-Traversal.md

@@ -20,7 +20,10 @@ tag:#DFS
  
 - [[Leetcode Binary-Tree-Inorder-Traversal]]
 - [[Leetcode Binary-Tree-Postorder-Traversal]]
+- [[Leetcode Invert-Binary-Tree]]
 - [[Leetcode Maximum-Depth-Of-Binary-Tree]]
+- [[Leetcode Path-Sum]]
+- [[Leetcode Search-In-a-Binary-Tree]]
 - [[Leetcode Symmetric-Tree]]
  
 

CS notes/pages/Leetcode Invert-Binary-Tree.md

@@ -18,6 +18,8 @@
 tag:#recursion tag:#DFS
 ```
  
+- [[Leetcode Path-Sum]]
+- [[Leetcode Symmetric-Tree]]
  
 
 ##### Links:

CS notes/pages/Leetcode Maximum-Depth-Of-Binary-Tree.md

@@ -19,6 +19,7 @@ tag:#BFS
 ```
  
 - [[Leetcode Binary-Tree-Level-Order-Traversal]]
+- [[Leetcode Search-In-a-Binary-Tree]]
  
 
 ##### Links:

CS notes/pages/Leetcode Path-Sum.md

@@ -18,6 +18,13 @@
 tag:#DFS
 ```
  
+- [[Leetcode Binary-Tree-Inorder-Traversal]]
+- [[Leetcode Binary-Tree-Postorder-Traversal]]
+- [[Leetcode Binary-Tree-Preorder-Traversal]]
+- [[Leetcode Invert-Binary-Tree]]
+- [[Leetcode Maximum-Depth-Of-Binary-Tree]]
+- [[Leetcode Search-In-a-Binary-Tree]]
+- [[Leetcode Symmetric-Tree]]
  
 
 ##### Links:

CS notes/pages/Leetcode Search-In-a-Binary-Tree.md

@@ -0,0 +1,146 @@
+# Leetcode Search-In-a-Binary-Tree
+
+#### 2022-07-07 08:06
+
+> ##### Algorithms:
+> #algorithm #DFS #BFS
+> ##### Data structures:
+> #DS #binary_tree 
+> ##### Difficulty:
+> #coding_problem #difficulty-easy 
+> ##### Additional tags:
+> #leetcode 
+> ##### Revisions:
+> N/A
+
+##### Related topics:
+```expander
+tag:#DFS OR tag:#BFS
+```
+ 
+- [[Leetcode Binary-Tree-Inorder-Traversal]]
+- [[Leetcode Binary-Tree-Level-Order-Traversal]]
+- [[Leetcode Binary-Tree-Postorder-Traversal]]
+- [[Leetcode Binary-Tree-Preorder-Traversal]]
+- [[Leetcode Invert-Binary-Tree]]
+- [[Leetcode Maximum-Depth-Of-Binary-Tree]]
+- [[Leetcode Path-Sum]]
+- [[Leetcode Symmetric-Tree]]
+ 
+
+##### Links:
+- [Link to problem](https://leetcode.com/problems/search-in-a-binary-search-tree/submissions/)
+___
+### Problem
+
+You are given the `root` of a binary search tree (BST) and an integer `val`.
+
+Find the node in the BST that the node's value equals `val` and return the subtree rooted with that node. If such a node does not exist, return `null`.
+
+#### Examples
+
+Example 1:
+
+Input: root = [4,2,7,1,3], val = 2
+Output: [2,1,3]
+
+Example 2:
+
+Input: root = [4,2,7,1,3], val = 5
+Output: []
+
+
+
+#### Constraints
+
+-   The number of nodes in the tree is in the range `[1, 5000]`.
+-   `1 <= Node.val <= 107`
+-   `root` is a binary search tree.
+-   `1 <= val <= 107`
+
+### Thoughts
+
+> [!summary]
+> This is a #DFS or #BFS problem. We search values in the tree.
+
+### Solution
+
+DFS
+```cpp
+/**
+ * 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:
+  TreeNode *searchBST(TreeNode *root, int val) {
+    // DFS preorder
+    // Base cases
+    if (!root) {
+      return nullptr;
+    }
+    if (root->val == val) {
+      return root;
+    }
+
+    auto left = searchBST(root->left, val);
+    if (left) {
+      return left;
+    }
+    auto right = searchBST(root->right, val);
+    if (right) {
+      return right;
+    }
+
+    // left and right not found
+    return nullptr;
+  }
+};
+```
+
+Which can be simplified to 
+```cpp
+/**
+ * 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:
+  TreeNode* searchBST(TreeNode* root, int val) {
+    // DFS preorder
+    // Base cases
+    if (!root) {
+      return nullptr;
+    }
+    if (root->val == val) {
+      return root;
+    }
+    
+    auto left = searchBST(root->left, val);
+    if (left) {
+      return left;
+    }
+    return searchBST(root->right, val);
+  }
+};
+```
+
+BFS
+```cpp
+
+```

CS notes/pages/Leetcode Symmetric-Tree.md

@@ -19,6 +19,7 @@ tag:#DFS or tag:#BFS
 ```
  
 - [[Leetcode Maximum-Depth-Of-Binary-Tree]]
+- [[Leetcode Search-In-a-Binary-Tree]]
  
 
 ##### Links: