great-problems-for-practice.md

Great Problems For Practice

215. Kth Largest Element in an Array (Medium): Quick Select; Manually Implement Heap; API usage of nth_element, make_heap, push_heap, pop_heap

1235. Maximum Profit in Job Scheduling (Hard): DP + Binary search because of sparse value (compared to continuous indexes)

1830. Minimum Number of Operations to Make String Sorted (Hard): permutation rank with duplicates

472. Concatenated Words (Hard): Trie + DP

DP on Subsets OR Backtrack to Fill Buckets

• 698. Partition to K Equal Sum Subsets (Medium)
• 473. Matchsticks to Square (Medium)
• 1723. Find Minimum Time to Finish All Jobs (Hard)

Geometry

• 478. Generate Random Point in a Circle (Medium)

Trie + XOR

• 421. Maximum XOR of Two Numbers in an Array (Medium)
• 1707. Maximum XOR With an Element From Array (Hard)
• 1803. Count Pairs With XOR in a Range (Hard)

BIT (Binary Index Tree) or Segment Tree

• 307. Range Sum Query - Mutable (Medium)

Backtracking

• 51. N-Queens (Hard)
• 698. Partition to K Equal Sum Subsets (Medium)
• 473. Matchsticks to Square (Medium)

Stack operation on string

• 1003. Check If Word Is Valid After Substitutions (Medium)
• 1209. Remove All Adjacent Duplicates in String II (Medium)

Permutation

• 60. Permutation Sequence (Hard)
• 31. Next Permutation (Medium)

Mono Stack / Mono Deque

• 907. Sum of Subarray Minimums (Medium)

Sorting

• 912. Sort an Array (Medium)

Binary Indexed Tree

• 307. Range Sum Query - Mutable (Medium)