engr-hasanuzzaman · December 26, 2019 05:56 · Dec 25, 2019 · Dec 23, 2019 · Dec 2, 2019 · Dec 2, 2019
diff --git a/LeetCodeQuestions.md b/LeetCodeQuestions.md
@@ -29,7 +29,7 @@
 - [ ] [Climbing Stairs](https://leetcode.com/problems/climbingstairs/)
 - [ ] [Coin Change](https://leetcode.com/problems/coinchange/)
 - [ ] [Longest Increasing Subsequence](https://leetcode.com/problems/longestincreasingsubsequence/)
-- [ ] [Longest Common Subsequence]()
+- [ ] [Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence/)
 - [ ] [Word Break Problem](https://leetcode.com/problems/wordbreak/)
 - [ ] [Combination Sum](https://leetcode.com/problems/combinationsumiv/)
 - [ ] [House Robber](https://leetcode.com/problems/houserobber/)

diff --git a/LeetCodeQuestions.md b/LeetCodeQuestions.md
@@ -122,3 +122,5 @@
 - [ ] [Top K Frequent Elements](https://leetcode.com/problems/topkfrequentelements/)
 - [ ] [Find Median from Data Stream](https://leetcode.com/problems/findmedianfromdatastream/)
 
+## Important Link:
+[14 Patterns to Ace Any Coding Interview Question](https://hackernoon.com/14-patterns-to-ace-any-coding-interview-question-c5bb3357f6ed)
diff --git a/LeetCodeQuestions.md b/LeetCodeQuestions.md
@@ -84,41 +84,41 @@
 
 ## String
 
-- [] [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longestsubstringwithoutrepeatingcharacters/)
-- [] [Longest Repeating Character Replacement](https://leetcode.com/problems/longestrepeatingcharacterreplacement/)
-- [] [Minimum Window Substring](https://leetcode.com/problems/minimumwindowsubstring/)
-- [] [Valid Anagram](https://leetcode.com/problems/validanagram/)
-- [] [Group Anagrams](https://leetcode.com/problems/groupanagrams/)
-- [] [Valid Parentheses](https://leetcode.com/problems/validparentheses/)
-- [] [Valid Palindrome](https://leetcode.com/problems/validpalindrome/)
-- [] [Longest Palindromic Substring](https://leetcode.com/problems/longestpalindromicsubstring/)
-- [] [Palindromic Substrings](https://leetcode.com/problems/palindromicsubstrings/)
-- [] [Encode and Decode Strings (Leetcode Premium)](https://leetcode.com/problems/encodeanddecodestrings/)
+- [ ] [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longestsubstringwithoutrepeatingcharacters/)
+- [ ] [Longest Repeating Character Replacement](https://leetcode.com/problems/longestrepeatingcharacterreplacement/)
+- [ ] [Minimum Window Substring](https://leetcode.com/problems/minimumwindowsubstring/)
+- [ ] [Valid Anagram](https://leetcode.com/problems/validanagram/)
+- [ ] [Group Anagrams](https://leetcode.com/problems/groupanagrams/)
+- [ ] [Valid Parentheses](https://leetcode.com/problems/validparentheses/)
+- [ ] [Valid Palindrome](https://leetcode.com/problems/validpalindrome/)
+- [ ] [Longest Palindromic Substring](https://leetcode.com/problems/longestpalindromicsubstring/)
+- [ ] [Palindromic Substrings](https://leetcode.com/problems/palindromicsubstrings/)
+- [ ] [Encode and Decode Strings (Leetcode Premium)](https://leetcode.com/problems/encodeanddecodestrings/)
 
 ---
 
 ## Tree
 
-- [] [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximumdepthofbinarytree/)
-- [] [Same Tree](https://leetcode.com/problems/sametree/)
-- [] [Invert/Flip Binary Tree](https://leetcode.com/problems/invertbinarytree/)
-- [] [Binary Tree Maximum Path Sum](https://leetcode.com/problems/binarytreemaximumpathsum/)
-- [] [Binary Tree Level Order Traversal](https://leetcode.com/problems/binarytreelevelordertraversal/)
-- [] [Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serializeanddeserializebinarytree/)
-- [] [Subtree of Another Tree](https://leetcode.com/problems/subtreeofanothertree/)
-- [] [Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/constructbinarytreefrompreorderandinordertraversal/)
-- [] [Validate Binary Search Tree](https://leetcode.com/problems/validatebinarysearchtree/)
-- [] [Kth Smallest Element in a BST](https://leetcode.com/problems/kthsmallestelementinabst/)
-- [] [Lowest Common Ancestor of BST](https://leetcode.com/problems/lowestcommonancestorofabinarysearchtree/)
-- [] [Implement Trie (Prefix Tree)](https://leetcode.com/problems/implementtrieprefixtree/)
-- [] [Add and Search Word](https://leetcode.com/problems/addandsearchworddatastructuredesign/)
-- [] [Word Search II](https://leetcode.com/problems/wordsearchii/)
+- [ ] [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximumdepthofbinarytree/)
+- [ ] [Same Tree](https://leetcode.com/problems/sametree/)
+- [ ] [Invert/Flip Binary Tree](https://leetcode.com/problems/invertbinarytree/)
+- [ ] [Binary Tree Maximum Path Sum](https://leetcode.com/problems/binarytreemaximumpathsum/)
+- [ ] [Binary Tree Level Order Traversal](https://leetcode.com/problems/binarytreelevelordertraversal/)
+- [ ] [Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serializeanddeserializebinarytree/)
+- [ ] [Subtree of Another Tree](https://leetcode.com/problems/subtreeofanothertree/)
+- [ ] [Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/constructbinarytreefrompreorderandinordertraversal/)
+- [ ] [Validate Binary Search Tree](https://leetcode.com/problems/validatebinarysearchtree/)
+- [ ] [Kth Smallest Element in a BST](https://leetcode.com/problems/kthsmallestelementinabst/)
+- [ ] [Lowest Common Ancestor of BST](https://leetcode.com/problems/lowestcommonancestorofabinarysearchtree/)
+- [ ] [Implement Trie (Prefix Tree)](https://leetcode.com/problems/implementtrieprefixtree/)
+- [ ] [Add and Search Word](https://leetcode.com/problems/addandsearchworddatastructuredesign/)
+- [ ] [Word Search II](https://leetcode.com/problems/wordsearchii/)
 
 ---
 
 ## Heap
 
-- [] [Merge K Sorted Lists](https://leetcode.com/problems/mergeksortedlists/)
-- [] [Top K Frequent Elements](https://leetcode.com/problems/topkfrequentelements/)
-- [] [Find Median from Data Stream](https://leetcode.com/problems/findmedianfromdatastream/)
+- [ ] [Merge K Sorted Lists](https://leetcode.com/problems/mergeksortedlists/)
+- [ ] [Top K Frequent Elements](https://leetcode.com/problems/topkfrequentelements/)
+- [ ] [Find Median from Data Stream](https://leetcode.com/problems/findmedianfromdatastream/)
 
diff --git a/LeetCodeQuestions.md b/LeetCodeQuestions.md
@@ -56,7 +56,7 @@
 
 - [ ] [Insert Interval](https://leetcode.com/problems/insertinterval/)
 - [ ] [Merge Intervals](https://leetcode.com/problems/mergeintervals/)
-- [ ] [Non-overlapping Intervals](overlapping Intervalshttps://leetcode.com/problems/nonoverlappingintervals/)
+- [ ] [Non-overlapping Intervals](https://leetcode.com/problems/nonoverlappingintervals/)
 - [ ] [Meeting Rooms (Leetcode Premium)](https://leetcode.com/problems/meetingrooms/)
 - [ ] [Meeting Rooms II (Leetcode Premium)](https://leetcode.com/problems/meetingroomsii/)
 

diff --git a/LeetCodeQuestions.md b/LeetCodeQuestions.md
@@ -42,43 +42,43 @@
 
 ## Graph
 
-- [] [Clone Graph](https://leetcode.com/problems/clonegraph/)
-- [] [Course Schedule](https://leetcode.com/problems/courseschedule/)
-- [] [Pacific Atlantic Water Flow](https://leetcode.com/problems/pacificatlanticwaterflow/)
-- [] [Number of Islands](https://leetcode.com/problems/numberofislands/)
-- [] [Longest Consecutive Sequence](https://leetcode.com/problems/longestconsecutivesequence/)
-- [] [Alien Dictionary (Leetcode Premium)](https://leetcode.com/problems/aliendictionary/)
-- [] [Graph Valid Tree (Leetcode Premium)](https://leetcode.com/problems/graphvalidtree/)
-- [] [Number of Connected Components in an Undirected Graph (Leetcode Premium)](https://leetcode.com/problems/numberofconnectedcomponentsinanundirectedgraph/)
+- [ ] [Clone Graph](https://leetcode.com/problems/clonegraph/)
+- [ ] [Course Schedule](https://leetcode.com/problems/courseschedule/)
+- [ ] [Pacific Atlantic Water Flow](https://leetcode.com/problems/pacificatlanticwaterflow/)
+- [ ] [Number of Islands](https://leetcode.com/problems/numberofislands/)
+- [ ] [Longest Consecutive Sequence](https://leetcode.com/problems/longestconsecutivesequence/)
+- [ ] [Alien Dictionary (Leetcode Premium)](https://leetcode.com/problems/aliendictionary/)
+- [ ] [Graph Valid Tree (Leetcode Premium)](https://leetcode.com/problems/graphvalidtree/)
+- [ ] [Number of Connected Components in an Undirected Graph (Leetcode Premium)](https://leetcode.com/problems/numberofconnectedcomponentsinanundirectedgraph/)
 ---
 
 ## Interval
 
-- [] [Insert Interval](https://leetcode.com/problems/insertinterval/)
-- [] [Merge Intervals](https://leetcode.com/problems/mergeintervals/)
-- [] [Non](overlapping Intervalshttps://leetcode.com/problems/nonoverlappingintervals/)
-- [] [Meeting Rooms (Leetcode Premium)](https://leetcode.com/problems/meetingrooms/)
-- [] [Meeting Rooms II (Leetcode Premium)](https://leetcode.com/problems/meetingroomsii/)
+- [ ] [Insert Interval](https://leetcode.com/problems/insertinterval/)
+- [ ] [Merge Intervals](https://leetcode.com/problems/mergeintervals/)
+- [ ] [Non-overlapping Intervals](overlapping Intervalshttps://leetcode.com/problems/nonoverlappingintervals/)
+- [ ] [Meeting Rooms (Leetcode Premium)](https://leetcode.com/problems/meetingrooms/)
+- [ ] [Meeting Rooms II (Leetcode Premium)](https://leetcode.com/problems/meetingroomsii/)
 
 ---
 
 ## Linked List
 
-- [] [Reverse a Linked List](https://leetcode.com/problems/reverselinkedlist/)
-- [] [Detect Cycle in a Linked List](https://leetcode.com/problems/linkedlistcycle/)
-- [] [Merge Two Sorted Lists](https://leetcode.com/problems/mergetwosortedlists/)
-- [] [Merge K Sorted Lists](https://leetcode.com/problems/mergeksortedlists/)
-- [] [Remove Nth Node From End Of List](https://leetcode.com/problems/removenthnodefromendoflist/)
-- [] [Reorder List](https://leetcode.com/problems/reorderlist/)
+- [ ] [Reverse a Linked List](https://leetcode.com/problems/reverselinkedlist/)
+- [ ] [Detect Cycle in a Linked List](https://leetcode.com/problems/linkedlistcycle/)
+- [ ] [Merge Two Sorted Lists](https://leetcode.com/problems/mergetwosortedlists/)
+- [ ] [Merge K Sorted Lists](https://leetcode.com/problems/mergeksortedlists/)
+- [ ] [Remove Nth Node From End Of List](https://leetcode.com/problems/removenthnodefromendoflist/)
+- [ ] [Reorder List](https://leetcode.com/problems/reorderlist/)
 
 ---
 
 ## Matrix
 
-- [] [Set Matrix Zeroes](https://leetcode.com/problems/setmatrixzeroes/)
-- [] [Spiral Matrix](https://leetcode.com/problems/spiralmatrix/)
-- [] [Rotate Image](https://leetcode.com/problems/rotateimage/)
-- [] [Word Search](https://leetcode.com/problems/wordsearch/)
+- [ ] [Set Matrix Zeroes](https://leetcode.com/problems/setmatrixzeroes/)
+- [ ] [Spiral Matrix](https://leetcode.com/problems/spiralmatrix/)
+- [ ] [Rotate Image](https://leetcode.com/problems/rotateimage/)
+- [ ] [Word Search](https://leetcode.com/problems/wordsearch/)
 
 ---
 

diff --git a/LeetCodeQuestions.md b/LeetCodeQuestions.md
@@ -1,42 +1,42 @@
 
 ## Array
 
-- [] [Two Sum](https://leetcode.com/problems/two-sum/)
-- [] [Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)
-- [] [Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)
-- [] [Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self/)
-- [] [Maximum Subarray](https://leetcode.com/problems/maximum-subarray/)
-- [] [Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/)
-- [] [Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/)
-- [] [Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/)
-- [] [3Sum](https://leetcode.com/problems/3sum/)
-- [] [Container With Most Water](https://leetcode.com/problems/container-with-most-water/)
+- [ ] [Two Sum](https://leetcode.com/problems/two-sum/)
+- [ ] [Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)
+- [ ] [Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)
+- [ ] [Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self/)
+- [ ] [Maximum Subarray](https://leetcode.com/problems/maximum-subarray/)
+- [ ] [Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/)
+- [ ] [Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/)
+- [ ] [Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/)
+- [ ] [3Sum](https://leetcode.com/problems/3sum/)
+- [ ] [Container With Most Water](https://leetcode.com/problems/container-with-most-water/)
 
 ---
 
 ## Binary
 
-- [] [Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers/)
-- [] [Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/)
-- [] [Counting Bits](https://leetcode.com/problems/counting-bits/)
-- [] [Missing Number](https://leetcode.com/problems/missing-number/)
-- [] [Reverse Bits](https://leetcode.com/problems/reverse-bits/)
+- [ ] [Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers/)
+- [ ] [Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/)
+- [ ] [Counting Bits](https://leetcode.com/problems/counting-bits/)
+- [ ] [Missing Number](https://leetcode.com/problems/missing-number/)
+- [ ] [Reverse Bits](https://leetcode.com/problems/reverse-bits/)
 
 ---
 
 ## Dynamic Programming
 
-- [] [Climbing Stairs](https://leetcode.com/problems/climbingstairs/)
-- [] [Coin Change](https://leetcode.com/problems/coinchange/)
-- [] [Longest Increasing Subsequence](https://leetcode.com/problems/longestincreasingsubsequence/)
-- [] [Longest Common Subsequence]()
-- [] [Word Break Problem](https://leetcode.com/problems/wordbreak/)
-- [] [Combination Sum](https://leetcode.com/problems/combinationsumiv/)
-- [] [House Robber](https://leetcode.com/problems/houserobber/)
-- [] [House Robber II](https://leetcode.com/problems/houserobberii/)
-- [] [Decode Ways](https://leetcode.com/problems/decodeways/)
-- [] [Unique Paths](https://leetcode.com/problems/uniquepaths/)
-- [] [Jump Game](https://leetcode.com/problems/jumpgame/)
+- [ ] [Climbing Stairs](https://leetcode.com/problems/climbingstairs/)
+- [ ] [Coin Change](https://leetcode.com/problems/coinchange/)
+- [ ] [Longest Increasing Subsequence](https://leetcode.com/problems/longestincreasingsubsequence/)
+- [ ] [Longest Common Subsequence]()
+- [ ] [Word Break Problem](https://leetcode.com/problems/wordbreak/)
+- [ ] [Combination Sum](https://leetcode.com/problems/combinationsumiv/)
+- [ ] [House Robber](https://leetcode.com/problems/houserobber/)
+- [ ] [House Robber II](https://leetcode.com/problems/houserobberii/)
+- [ ] [Decode Ways](https://leetcode.com/problems/decodeways/)
+- [ ] [Unique Paths](https://leetcode.com/problems/uniquepaths/)
+- [ ] [Jump Game](https://leetcode.com/problems/jumpgame/)
 
 ---
 

diff --git a/LeetCodeQuestions.md b/LeetCodeQuestions.md
@@ -0,0 +1,124 @@
+
+## Array
+
+- [] [Two Sum](https://leetcode.com/problems/two-sum/)
+- [] [Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)
+- [] [Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)
+- [] [Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self/)
+- [] [Maximum Subarray](https://leetcode.com/problems/maximum-subarray/)
+- [] [Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/)
+- [] [Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/)
+- [] [Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/)
+- [] [3Sum](https://leetcode.com/problems/3sum/)
+- [] [Container With Most Water](https://leetcode.com/problems/container-with-most-water/)
+
+---
+
+## Binary
+
+- [] [Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers/)
+- [] [Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/)
+- [] [Counting Bits](https://leetcode.com/problems/counting-bits/)
+- [] [Missing Number](https://leetcode.com/problems/missing-number/)
+- [] [Reverse Bits](https://leetcode.com/problems/reverse-bits/)
+
+---
+
+## Dynamic Programming
+
+- [] [Climbing Stairs](https://leetcode.com/problems/climbingstairs/)
+- [] [Coin Change](https://leetcode.com/problems/coinchange/)
+- [] [Longest Increasing Subsequence](https://leetcode.com/problems/longestincreasingsubsequence/)
+- [] [Longest Common Subsequence]()
+- [] [Word Break Problem](https://leetcode.com/problems/wordbreak/)
+- [] [Combination Sum](https://leetcode.com/problems/combinationsumiv/)
+- [] [House Robber](https://leetcode.com/problems/houserobber/)
+- [] [House Robber II](https://leetcode.com/problems/houserobberii/)
+- [] [Decode Ways](https://leetcode.com/problems/decodeways/)
+- [] [Unique Paths](https://leetcode.com/problems/uniquepaths/)
+- [] [Jump Game](https://leetcode.com/problems/jumpgame/)
+
+---
+
+## Graph
+
+- [] [Clone Graph](https://leetcode.com/problems/clonegraph/)
+- [] [Course Schedule](https://leetcode.com/problems/courseschedule/)
+- [] [Pacific Atlantic Water Flow](https://leetcode.com/problems/pacificatlanticwaterflow/)
+- [] [Number of Islands](https://leetcode.com/problems/numberofislands/)
+- [] [Longest Consecutive Sequence](https://leetcode.com/problems/longestconsecutivesequence/)
+- [] [Alien Dictionary (Leetcode Premium)](https://leetcode.com/problems/aliendictionary/)
+- [] [Graph Valid Tree (Leetcode Premium)](https://leetcode.com/problems/graphvalidtree/)
+- [] [Number of Connected Components in an Undirected Graph (Leetcode Premium)](https://leetcode.com/problems/numberofconnectedcomponentsinanundirectedgraph/)
+---
+
+## Interval
+
+- [] [Insert Interval](https://leetcode.com/problems/insertinterval/)
+- [] [Merge Intervals](https://leetcode.com/problems/mergeintervals/)
+- [] [Non](overlapping Intervalshttps://leetcode.com/problems/nonoverlappingintervals/)
+- [] [Meeting Rooms (Leetcode Premium)](https://leetcode.com/problems/meetingrooms/)
+- [] [Meeting Rooms II (Leetcode Premium)](https://leetcode.com/problems/meetingroomsii/)
+
+---
+
+## Linked List
+
+- [] [Reverse a Linked List](https://leetcode.com/problems/reverselinkedlist/)
+- [] [Detect Cycle in a Linked List](https://leetcode.com/problems/linkedlistcycle/)
+- [] [Merge Two Sorted Lists](https://leetcode.com/problems/mergetwosortedlists/)
+- [] [Merge K Sorted Lists](https://leetcode.com/problems/mergeksortedlists/)
+- [] [Remove Nth Node From End Of List](https://leetcode.com/problems/removenthnodefromendoflist/)
+- [] [Reorder List](https://leetcode.com/problems/reorderlist/)
+
+---
+
+## Matrix
+
+- [] [Set Matrix Zeroes](https://leetcode.com/problems/setmatrixzeroes/)
+- [] [Spiral Matrix](https://leetcode.com/problems/spiralmatrix/)
+- [] [Rotate Image](https://leetcode.com/problems/rotateimage/)
+- [] [Word Search](https://leetcode.com/problems/wordsearch/)
+
+---
+
+## String
+
+- [] [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longestsubstringwithoutrepeatingcharacters/)
+- [] [Longest Repeating Character Replacement](https://leetcode.com/problems/longestrepeatingcharacterreplacement/)
+- [] [Minimum Window Substring](https://leetcode.com/problems/minimumwindowsubstring/)
+- [] [Valid Anagram](https://leetcode.com/problems/validanagram/)
+- [] [Group Anagrams](https://leetcode.com/problems/groupanagrams/)
+- [] [Valid Parentheses](https://leetcode.com/problems/validparentheses/)
+- [] [Valid Palindrome](https://leetcode.com/problems/validpalindrome/)
+- [] [Longest Palindromic Substring](https://leetcode.com/problems/longestpalindromicsubstring/)
+- [] [Palindromic Substrings](https://leetcode.com/problems/palindromicsubstrings/)
+- [] [Encode and Decode Strings (Leetcode Premium)](https://leetcode.com/problems/encodeanddecodestrings/)
+
+---
+
+## Tree
+
+- [] [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximumdepthofbinarytree/)
+- [] [Same Tree](https://leetcode.com/problems/sametree/)
+- [] [Invert/Flip Binary Tree](https://leetcode.com/problems/invertbinarytree/)
+- [] [Binary Tree Maximum Path Sum](https://leetcode.com/problems/binarytreemaximumpathsum/)
+- [] [Binary Tree Level Order Traversal](https://leetcode.com/problems/binarytreelevelordertraversal/)
+- [] [Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serializeanddeserializebinarytree/)
+- [] [Subtree of Another Tree](https://leetcode.com/problems/subtreeofanothertree/)
+- [] [Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/constructbinarytreefrompreorderandinordertraversal/)
+- [] [Validate Binary Search Tree](https://leetcode.com/problems/validatebinarysearchtree/)
+- [] [Kth Smallest Element in a BST](https://leetcode.com/problems/kthsmallestelementinabst/)
+- [] [Lowest Common Ancestor of BST](https://leetcode.com/problems/lowestcommonancestorofabinarysearchtree/)
+- [] [Implement Trie (Prefix Tree)](https://leetcode.com/problems/implementtrieprefixtree/)
+- [] [Add and Search Word](https://leetcode.com/problems/addandsearchworddatastructuredesign/)
+- [] [Word Search II](https://leetcode.com/problems/wordsearchii/)
+
+---
+
+## Heap
+
+- [] [Merge K Sorted Lists](https://leetcode.com/problems/mergeksortedlists/)
+- [] [Top K Frequent Elements](https://leetcode.com/problems/topkfrequentelements/)
+- [] [Find Median from Data Stream](https://leetcode.com/problems/findmedianfromdatastream/)
+