Linked List
Stack
Queue
Tree
Heap - Min & Max
N-ary Tree
P3 - Longest Substring Without Repeating Characters (Medium)
P5 - Longest Palindromic Substring (Medium)
P6 - ZigZag Conversion (Medium)
P8 - String to Integer (atoi) (Medium)
P13 - Roman to Integer (Easy)
P14 - Longest Common Prefix (Easy)
P17 - Letter Combinations of a Phone Number (Medium)
P20 - Valid Parentheses (Easy)
P22 - Generate Parentheses (Medium)
P28 - Implement strStr() (Easy)
P38 - Count and Say (Easy)
P43 - Multiply Strings (Medium)
P49 - Group Anagrams (Medium)
P58 - Length of Last Word (Easy)
P67 - Add Binary (Easy)
P71 - Simplify Path (Medium)
P91 - Decode Ways (Medium)
P93 - Restore IP Addresses (Medium)
P125 - Valid Palindrome (Easy)
P151 - Reverse Words in a String (Medium)
P165 - Compare Version Numbers (Medium)
P227 - Basic Calculator II (Medium)
P316 - Remove Duplicate Letters (Hard) Same as P1081
P344 - Reverse String (Easy)
P345 - Reverse Vowels of a String (Easy)
P383 - Ransom Note (Easy)
P385 - Mini Parser (Medium)
P387 - First Unique Character in a String (Easy)
P394 - Decode String (Medium)
P415 - Add Strings (Easy)
P434 - Number of Segments in a String (Easy)
P438 - Find All Anagrams in a String (Medium)
P443 - String Compression (Easy)
P459 - Repeated Substring Pattern (Easy)
P468 - Validate IP Address (Medium)
P520 - Detect Capital (Easy)
P522 - Longest Uncommon Subsequence II (Medium)
P537 - Complex Number Multiplication (Medium)
P539 - Minimum Time Difference (Medium)
P541 - Reverse String II (Easy)
P553 - Optimal Division (Medium)
P556 - Next Greater Element III (Medium)
P557 - Reverse Words in a String III (Easy)
P567 - Permutation in String (Medium)
P583 - Delete Operation for Two Strings (Medium)
P606 - Construct String from Binary Tree (Easy)
P609 - Find Duplicate File in System (Medium)
P647 - Palindromic Substrings (Medium)
P657 - Robot Return to Origin (Easy)
P678 - Valid Parenthesis String (Medium)
P680 - Valid Palindrome II (Easy)
P696 - Count Binary Substrings (Easy)
P709 - To Lower Case (Easy)
P722 - Remove Comments (Medium)
P767 - Reorganize String (Medium)
P788 - Rotated Digits (Easy)
P791 - Custom Sort String (Medium)
P804 - Unique Morse Code Words (Easy)
P809 - Expressive Words (Medium)
P816 - Ambiguous Coordinates (Medium)
P819 - Most Common Word (Easy)
P824 - Goat Latin (Easy)
P831 - Masking Personal Information (Medium)
P842 - Split Array into Fibonacci Sequence (Medium)
P848 - Shifting Letters (Medium)
P856 - Score of Parentheses (Medium)
P859 - Buddy Strings (Easy)
P890 - Find and Replace Pattern (Medium)
P893 - Groups of Special-Equivalent Strings (Easy)
P916 - Word Subsets (Medium)
P917 - Reverse Only Letters (Easy)
P925 - Long Pressed Name (Easy)
P929 - Unique Email Addresses (Easy)
P937 - Reorder Data in Log Files (Easy)
P942 - DI String Match (Easy)
P966 - Vowel Spellchecker (Medium)
P984 - String Without AAA or BBB (Medium)
P1003 - Check If Word Is Valid After Substitutions (Medium)
P1016 - Binary String With Substrings Representing 1 To N (Medium)
P1021 - Remove Outermost Parentheses (Easy)
P1023 - Camelcase Matching (Medium)
P1047 - Remove All Adjacent Duplicates In String (Easy)
P1048 - Longest String Chain (Medium)
P1071 - Greatest Common Divisor of Strings (Easy)
P1081 - Smallest Subsequence of Distinct Characters (Medium)
P1108 - Defanging an IP Address (Easy)
P1119 - Remove Vowels from a String (Easy)
P1138 - Alphabet Board Path (Medium)
P1156 - Swap For Longest Repeated Character Substring (Medium)
P1169 - Invalid Transactions (Medium)
P1170 - Compare Strings by Frequency of the Smallest Character (Easy)
P1177 - Can Make Palindrome from Substring (Medium)
P1189 - Maximum Number of Balloons (Easy)
P1209 - Remove All Adjacent Duplicates in String II (Medium)
P1221 - Split a String in Balanced Strings (Easy)
P1233 - Remove Sub-Folders from the Filesystem (Medium)
P1234 - Replace the Substring for Balanced String (Medium)
P1247 - Minimum Swaps to Make Strings Equal (Medium)
P1268 - Search Suggestions System (Medium)
P1297 - Maximum Number of Occurrences of a Substring (Medium)
P1309 - Decrypt String from Alphabet to Integer Mapping (Easy)
P1311 - Get Watched Videos by Your Friends (Medium)
P1312 - Minimum Insertion Steps to Make a String Palindrome (Medium)
P1324 - Print Words Vertically (Medium)
P1328 - Break a Palindrome (Medium)
P1332 - Remove Palindromic Subsequences (Easy)
P1347 - Minimum Number of Steps to Make Two Strings Anagram (Medium)
P1358 - Number of Substrings Containing All Three Characters (Medium)
P1370 - Increasing Decreasing String (Easy)
P1371 - Find the Longest Substring Containing Vowels in Even Counts (Medium)
P1374 - Generate a String With Characters That Have Odd Counts (Easy)
P81 - Search in Rotated Sorted Array II (Medium)
P153 - Find Minimum in Rotated Sorted Array (Medium)
P153 - Find Minimum in Rotated Sorted Array with duplicates (Hard)
P167 - Two Sum II - Input array is sorted (Easy)
P189 - Rotate Array (Easy)
P215 - Kth Largest Element in an Array (Medium)
P330 - Patching Array (Hard)
P349 - Intersection of Two Arrays (Easy)
P360 - Sort Transformed Array (Medium)
P384 - Shuffle an Array (Easy)
P441 - Arranging Coins (Easy)
P442 - Find All Duplicates in an Array (Medium)
P448 - Find All Numbers Disappeared in an Array (Easy)
P457 - Circular Array Loop (Medium)
P521 - Longest Uncommon Subsequence I (Easy)
P525 - Contiguous Array (Medium)
P526 - Beautiful Arrangement (Medium)
P551 - Student Attendance Record I (Easy)
P561 - Array Partition I (Easy)
P565 - Array Nesting (Medium)
P629 - K Inverse Pairs Array (Hard)
P665 - Non-decreasing Array (Easy)
P686 - Repeated String Match (Easy)
P697 - Degree of an Array (Easy)
P805 - Split Array With Same Average (Hard)
P852 - Peak Index in a Mountain Array (Easy)
P869 - Find the Derangement of An Array (Medium)
P896 - Monotonic Array (Easy)
P905 - Sort Array By Parity (Easy)
P912 - Sort an Array (Easy)
P915 - Partition Array into Disjoint Intervals (Medium)
P932 - Beautiful Array (Medium)
P941 - Valid Mountain Array (Easy)
P961 - N-Repeated Element in Size 2N Array (Easy)
P977 - Squares of a Sorted Array (Easy)
P989 - Add to Array-Form of Integer (Easy)
P996 - Number of Squareful Arrays (Hard)
P1095 - Find in Mountain Array (Hard)
P1122 - Relative Sort Array (Easy)
P1146 - Snapshot Array (Medium)
P1213 - Intersection of Three Sorted Arrays (Easy)
P1243 - Array Transformation (Easy)
P1249 - Minimum Remove to Make Valid Parentheses (Medium)
P1250 - Check If It Is a Good Array (Hard)
P1295 - Find Numbers with Even Number of Digits (Easy)
P94 - Binary Tree Inorder Traversal (Medium)
P98 - Validate Binary Search Tree (Medium)
P100 - Same tree (Easy)
P101 - Symmetric tree (Easy)
P102 - Binary Tree Level Order Traversal (Medium)
P104 - Maximum Depth of Binary Tree (Easy)
P107 - Binary Tree Level Order Traversal II (Easy)
P108 - Convert Sorted List to Binary Search Tree (Medium)
P110 - Is balanced tree (Easy)
P111 - Minimum Depth of Binary Tree (Easy)
P112 - Path Sum (Easy)
P114 - Flatten to linked list (Medium)
P117 - Populating Next Right Pointers in Each Node II (Medium)
P144 - Binary Tree Preorder Traversal (Medium)
P173 - Binary Search Tree Iterator (Medium)
P199 - Print Right View (Medium)
P222 - Count Complete Tree Nodes (Medium)
P226 - Invert tree (Easy)
P230 - Kth Smallest Element in a BST (Medium)
P235 - Lowest Common Ancestor of a Binary Search Tree (Easy)
P257 - Binary Tree Paths (Easy)
P310 - Minimum Height Trees (Medium)
P366 - Find Leaves of Binary Tree (Medium)
P404 - Sum of Left Leaves (Easy)
P429 - N-ary Tree Level Order Traversal (Medium)
P437 - Path Sum III (Easy)
P501 - Find Mode in Binary Search Tree (Easy)
P508 - Most Frequent Subtree Sum (Medium)
P513 - Find Bottom Left Tree Value (Medium)
P515 - Find Largest Value in Each Tree Row (Medium)
P538 - Convert to greatest BST (Easy)
P530 - Minimum Absolute Difference in BST (Easy) - P783
P543 - Diameter of Binary Tree (Easy)
P545 - Boundary of Binary Tree (Medium)
P549 - Binary Tree Longest Consecutive Sequence II (Medium)
P558 - Quad Tree Intersection (Easy)
P559 - Maximum Depth of N-ary Tree (Easy)
P563 - Binary Tree Tilt (Easy)
P572 - Is subtree (Easy)
P589 - N-ary Tree Preorder Traversal (Easy)
P590 - N-ary Tree Postorder Traversal (Easy)
P608 - Tree Node (Medium)
P617 - Merge Tree (Easy)
P623 - Add one row to tree (Medium)
P637 - Average of Levels in Binary Tree (Easy)
P653 - Two Sum IV - Input is a BST (Easy)
P654 - Maximum Binary Tree (Medium)
P662 - Maximum width (Medium)
P663 - Equal Tree Partition (Medium)
P655 - Print tree in matrix (Medium)
P669 - Trim a Binary Search Tree (Easy)
P671 - Second Minimum Node In a Binary Tree (Easy)
P684 - Redundant Connection (Medium)
P687 - Longest Univalue Path (Easy)
P700 - Search in a Binary Search Tree (Easy)
P701 - Insert into a Binary Search Tree (Medium)
P783 - Minimum Distance Between BST Nodes (Easy)
P814 - Binary tree pruning (Medium)
P865 - Smallest Subtree with all the Deepest Nodes (Medium)
P872 - Leaf-Similar Trees (Easy)
P889 - Construct Binary Tree from Preorder and Postorder Traversal (Medium)
P894 - All Possible Full Binary Trees (Medium)
P897 - Increasing Order Search Tree (Easy)
P919 - Complete Binary Tree Inserter (Medium)
P938 - Range Sum of BST (Easy)
P951 - Flip Equivalent Binary Trees (Medium)
P958 - Check Completeness of a Binary Tree (Medium)
P965 - Univalued Binary Tree (Easy)
P968 - Binary Tree Cameras (Hard)
P979 - Distribute Coins (Medium)
P987 - Vertical Order Traversal of a Binary Tree (Medium)
P993 - Cousins (Easy)
P998 - Maximum Binary Tree II (Medium)
P1008 - Construct Binary Search Tree from Preorder Traversal (Medium)
P1022 - Sum of Root To Leaf Binary Numbers (Easy)
P1026 - Maximum Difference Between Node and Ancestor (Medium)
P1028 - Recover a Tree From Preorder Traversal (Hard)
P1104 - Path In Zigzag Labelled Binary Tree (Medium)
P1110 - Delete Nodes And Return Forest (Medium)
P1123 - Lowest Common Ancestor of Deepest Leaves (Medium)
P1130 - Minimum Cost Tree From Leaf Values (Medium)
P1245 - Tree Diameter (Medium)
P1261 - Find Elements in a Contaminated Binary Tree (Medium)
P1302 - Deepest Leaves Sum (Medium)
P1305 - All Elements in Two Binary Search Trees (Medium)
P1315 - Sum of Nodes with Even-Valued Grandparent (Medium)
P1325 - Delete Leaves With a Given Value (Medium)
P1339 - Maximum Product of Splitted Binary Tree (Medium)
P1379 - Find a Corresponding Node of a Binary Tree in a Clone of That Tree (Medium)