Leetcode

Solutions for medium and hard problems

#	Problem	Difficulty	Tags	Solution
37	Sudoku Solver	Hard		python3
51	N-Queens	Hard		python3
57	Insert Interval	Medium		python3
62	Unique Paths	Medium		python3
63	Unique Paths II	Medium		python3
93	Restore IP Addresses	Medium		python3
128	Longest Consecutive Sequence	Medium		python3
131	Palindrome Partitioning	Medium		python3
132	Palindrome Partitioning II	Hard	dynamic-programming	python3
134	Gas Station	Medium		python3
149	Max Points on a Line	Hard		python3
224	Basic Calculator	Hard		python3
352	Data Stream as Disjoint Intervals	Hard		python3
452	Minimum Number of Arrows to Burst Balloons	Medium		python3
454	4Sum II	Medium		python3
491	Non-decreasing Subsequences	Medium		python3
684	Redundant Connection	Medium	union-find	python3
685	Redundant Connection II	Hard	union-find	python3
695	Max Area of Island	Medium	union-find	python3
721	Accounts Merge	Medium	union-find	python3
765	Couples Holding Hands	Hard	union-find	python3
787	Cheapest Flights Within K Stops	Medium		python3
909	Snakes and Ladders	Medium		python3
918	Maximum Sum Circular Subarray	Medium		python3
926	Flip String to Monotone Increasing	Medium		python3
974	Subarray Sums Divisible by K	Medium		python3
980	Unique Paths III	Hard		python3
1011	Capacity To Ship Packages Within D Days	Medium		python3
1015	Smallest Integer Divisible by K	Medium		python3
1036	Escape a Large Maze	Hard		python3
1061	Lexicographically Smallest Equivalent String	Medium	union-find	python3
1239	Maximum Length of a Concatenated String with Unique Characters	Medium		python3
1443	Minimum Time to Collect All Apples in a Tree	Medium		python3
1519	Number of Nodes in the Sub-Tree With the Same Label	Medium		python3
1833	Maximum Ice Cream Bars	Medium		python3
2244	Minimum Rounds to Complete All Tasks	Medium		python3
2246	Longest Path with Different Adjacent Characters	Medium		python3
2364	Count Number of Bad Pairs	Medium		python3
2421	Number of Good Paths	Hard	union-find	python3

References

Union Find

Also called Disjoint Set.

• Leetcode tag #union-find
• union-find by William Fiset

Dynamic Programming

• Leetcode tag #dynamic-programming