11 |
Container With Most Water |
Sliding Window |

12 |
Integer to Roman |
Math |

17 |
Letter Combinations of a Phone Number |
DFS, Recursion |

19 |
Remove Nth Node From End of List |
Linked List |

22 |
Generate Parentheses |
Recursion, Bit Manipulation |

29 |
Divide Two Integers (ver. 1) |
Bit Manipulation |

29 |
Divide Two Integers (ver. 2) |
Math |

31 |
Next Permutation |
Array, Math |

34 |
Find First and Last Position of Element in Sorted Array |
Binary Search |

45 |
Jump Game II |
Array |

48 |
Rotate Image |
Matrix |

63 |
Unique Paths II |
Matrix, DP |

71 |
Simplify Path |
Stack, Sliding Window |

86 |
Partition List |
Linked List |

102 |
Binary Tree Level Order Traversal |
Binary Tree, BFS, Level-Order, Queue |

105 |
Construct Binary Tree from Preorder and Inorder Traversal |
Binary Tree, Preorder, Inorder, Recursion |

109 |
Convert Sorted List to Binary Search Tree |
Tree, Linked List, In-Order, Recursion, Floyd's |

114 |
Flatten Binary Tree to Linked List |
Binary Tree, Pre-Order, Recursion |

120 |
Triangle |
DP |

128 |
Longest Consecutive Sequence |
Map, Array |

138 |
Copy List with Random Pointer |
Linked List |

150 |
Evaluate Reverse Polish Notation |
Math, Stack |

199 |
Binary Tree Right Side View |
Tree, BFS, DFS, Recursion |

240 |
Search a 2D Matrix II |
Matrix, Binary Search |

284 |
Peeking Iterator |
Class |

304 |
Range Sum Query 2D - Immutable |
Matrix, DP, Prefix Sum |

318 |
Maximum Product of Word Lengths |
Bit Manipulation |

322 |
Coin Change |
DFS, Recursion |

341 |
Flatten Nested List Iterator |
Class, Queue, Recursion |

376 |
Wiggle Subsequence |
Subsequence |

377 |
Combination Sum IV |
DP |

413 |
Arithmetic Slices |
Math |

417 |
Pacific Atlantic Water Flow |
DFS, Recursion, DP |

423 |
Reconstruct Original Digits from English |
Frequency Map |

462 |
Minimum Moves to Equal Array Elements II |
Math, Array |

473 |
Matchsticks to Square |
Backtracking, Recursion |

474 |
Ones and Zeros |
DP |

478 |
Generate Random Point in a Circle |
Math |

524 |
Longest Word in Dictionary through Deleting |
String |

535 |
Encode and Decode TinyURL |
Map |

538 |
Convert BST to Greater Tree |
Tree, Inorder |

554 |
Brick Wall |
Frequency Map |

576 |
Out of Boundary Paths |
DP |

581 |
Shortest Unsorted Continuous Subarray |
Array |

583 |
Delete Operation for Two Strings |
LCS, DP |

609 |
Find Duplicate File in System |
Map, String |

622 |
Design Circular Queue |
Linked List |

623 |
Add One Row to Tree |
Binary Tree, DFS, Recursion |

647 |
Palindromic Substrings |
Math |

665 |
Non-decreasing Array |
Array |

667 |
Beautiful Arrangement II |
Math |

669 |
Trim a Binary Tree |
Tree, Recursion |

684 |
Redundant Connection |
Union-Find, Graph |

695 |
Max Area of Island |
Matrix, DFS, Recursion |

714 |
Best Time to Buy and Sell Stock with Transaction Fee |
State Machine |

729 |
My Calendar I |
Class, Linked List |

752 |
Open the Lock |
Graph, BFS, Queue |

775 |
Global and Local Inversions |
Math |

784 |
Letter Case Permutation |
Recursion, DFS |

785 |
Is Graph Bipartite? |
BFS, Bit Manipulation |

795 |
Number of Subarrays with Bounded Maximum |
Math, Array |

816 |
Ambiguous Coordinates |
String |

820 |
Short Encoding of Words (ver. 1) |
Set |

820 |
Short Encoding of Words (ver. 2) |
Trie |

823 |
Binary Trees With Factors |
Binary Tree, Map, Math |

841 |
Keys and Rooms |
DFS |

856 |
Score of Parentheses |
Binary, Math |

869 |
Reordered Power of 2 |
Math |

870 |
Advantage Shuffle |
Array |

890 |
Find and Replace Pattern |
Map, Mask |

916 |
Word Subsets |
Frequency Map |

923 |
3Sum With Multiplicity |
Frequency Map, Combinatorics |

946 |
Validate Stack Sequences |
Stack, 2-Pointer |

966 |
Vowel Spellchecker |
Map, Set, Masking |

970 |
Powerful Integers |
Set |

971 |
Flip Binary Tree To Match Preorder Traversal |
Binary Tree, DFS, Recursion |

991 |
Broken Calculator |
Math |

1048 |
Longest String Chain |
Set, Map, DP |

1091 |
Shortest Path in Binary Matrix |
BFS, Matrix, Bit Manipulation |

1209 |
Remove All Adjacent Duplicates in String II |
Recursion, Stack |

1249 |
Minimum Remove to Make Valid Parentheses |
Stack |

1268 |
Search Suggestions System |
2-Pointer System |

1302 |
Deepest Leaves Sum |
BFS, Queue, DFS, Recursion |

1329 |
Sort the Matrix Diagonally |
Matrix |

1396 |
Design Underground System |
Class, Map |

1423 |
Maximum Points You Can Obtain from Cards |
Sliding Window |

1461 |
Check If a String Contains All Binary Codes of Size K |
Binary, Bit Manipulation |

1465 |
Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts |
Array, Math |

1551 |
Minimum Operations to Make Array Equal |
Math |

1631 |
Path With Minimum Effort |
BFS, Dijkstra's, Heap |

1642 |
Furthest Building You Can Reach |
Heap |

1663 |
Smallest String With A Given Numeric Value |
Math |

1673 |
Find the Most Competitive Subsequence |
Stack |

1675 |
Minimize Deviation in Array |
Heap |

1680 |
Concatenation of Consecutive Binary Numbers |
Binary, Bit Manipulation |

1690 |
Stone Game VII |
DP |

1695 |
Maximum Erasure Value |
Array, Sliding Window |

1696 |
Jump Game VI |
DP, Deque, In-Place, Sliding Window |

1717 |
Maximum Score From Removing Substrings (ver. 1) |
DP, Stack |

1717 |
Maximum Score From Removing Substrings (ver. 2) |
String |

1721 |
Swapping Nodes in a Linked List |
Linked List |

1734 |
Decode XORed Permutation |
Bitwise XOR, Math |

1737 |
Change Minimum Characters to Satisfy One of Three Conditions |
Frequency Map, Math |

1738 |
Find Kth Largest XOR Coordinate Value |
Bitwise XOR, DP, Heap, Math |

## Top comments (2)

Pretty cool Sean. I'll definitely keep eyes on this series.

Actually, I'll make it better. I'll study one of them a day.

Thanks!

You're welcome, Rafael!

I've been doing the daily leetcode challenge problem pretty much every day for the past 8 months, and I will definitely agree that a little bit each day really helps!