https://leetcode.com/problems/find-players-with-zero-or-one-losses/description/

[sorted winners list, sorted single lose list]

https://leetcode.com/problems/insert-delete-getrandom-o1/description/

Implement HashSet<Int> with random method.

https://leetcode.com/problems/unique-number-of-occurrences/description/

Are array frequencies unique.

https://leetcode.com/problems/climbing-stairs/description/

Ways to climb n stairs by 1 or 2 steps.

https://leetcode.com/problems/minimum-falling-path-sum/description/

Min sum moving bottom center, left, right in 2D matrix.

https://leetcode.com/problems/sum-of-subarray-minimums/description

Sum of minimums of all array ranges.

https://leetcode.com/problems/house-robber/description/

Max sum to rob non adjacent items in array.

https://leetcode.com/problems/set-mismatch/description

Return missing and duplicated number in 1..n array with one number replaced.

https://leetcode.com/problems/maximum-length-of-a-concatenated-string-with-unique-characters/description

Max length subsequence of strings array with unique chars.

https://leetcode.com/problems/pseudo-palindromic-paths-in-a-binary-tree/description/

Count can-form-a-palindrome paths root-leaf in a binary tree.

https://leetcode.com/problems/out-of-boundary-paths/description/

Number of paths from cell in grid to out of boundary.

https://leetcode.com/problems/k-inverse-pairs-array/description

Number of arrays of 1..n with k reversed order pairs.

https://leetcode.com/problems/number-of-submatrices-that-sum-to-target/description/

Count submatrix target sums.

https://leetcode.com/problems/implement-queue-using-stacks/description

Queue by 2 stacks.

https://leetcode.com/problems/evaluate-reverse-polish-notation/description

Solve Reverse Polish Notation.

https://leetcode.com/problems/daily-temperatures/description/

Array of distances to the next largest.

https://leetcode.com/problems/divide-array-into-arrays-with-max-difference/description

Split array into tripples with at most k difference.

https://leetcode.com/problems/sequential-digits/description

Numbers with sequential digits in low..high range.

https://leetcode.com/problems/partition-array-for-maximum-sum/description/

Max sum of partition array into chunks size of at most k filled with max value in chunk.