this is a personal

https://leetcode.com/problems/adding-spaces-to-a-string/description/


Insert spaces into string #medium

https://leetcode.com/problems/make-string-a-subsequence-using-cyclic-increments/description/


Increase some chars once to make a subsequence #medium

https://leetcode.com/problems/move-pieces-to-obtain-a-string/description/


Move L left and R right to match strings #medium

https://leetcode.com/problems/maximum-number-of-integers-to-choose-from-a-range-i/description/


Sum 1..n excluding banned until maxSum #medium

https://leetcode.com/problems/minimum-limit-of-balls-in-a-bag/description/


Max number after at most maxOperations of splitting #medium #binary_search

https://leetcode.com/problems/two-best-non-overlapping-events/description/

Max two non-overlapping intervals #medium #binary_search

https://leetcode.com/problems/special-array-ii/description/

Queries is all adjucents parity differ [i..j] #medium #two_pointers

https://leetcode.com/problems/find-longest-special-substring-that-occurs-thrice-i/description/

Max same-char 3-windows length #medium #sliding_window

https://leetcode.com/problems/maximum-beauty-of-an-array-after-applying-operation/description/


Max equal nums after adjusting to [-k..+k] #medium #binary_search #line_sweep

https://leetcode.com/problems/take-gifts-from-the-richest-pile/description/

Sum after k-Sqrt of tops in array #easy

https://leetcode.com/problems/find-score-of-an-array-after-marking-all-elements/description/

Sum of minimums in order excluding siblings #medium #monotonic_stack

https://leetcode.com/problems/continuous-subarrays/description/

Count subarrays with difference <= 2 #medium #monotonic_queue #tree_set

https://leetcode.com/problems/maximum-average-pass-ratio/description/

Arrange passed students to improve average score #medium #heap

https://leetcode.com/problems/final-array-state-after-k-multiplication-operations-i/description/

Mutliply k minimums #easy

https://leetcode.com/problems/construct-string-with-repeat-limit/description/


Max lexical ordered with repeat_limit string #medium #bucket_sort

https://leetcode.com/problems/final-prices-with-a-special-discount-in-a-shop/description/

Subtract next smaller value #easy #monotonic_stack

https://leetcode.com/problems/max-chunks-to-make-sorted/description/

Maximum independent chunks to merge-sort array #medium

https://leetcode.com/problems/reverse-odd-levels-of-binary-tree/description/

Odd-levels reversal in a perfect tree #medium #dfs #bfs #tree

https://leetcode.com/problems/maximum-number-of-k-divisible-components/description/

Max connected components divisible by k in graph #hard #toposort

https://leetcode.com/problems/find-building-where-alice-and-bob-can-meet/description/

Common indices t, h[t] > h[a], h[t] > h[b] for queries q[][a,b] #hard #monotonic_stack