Array

LeetCode 599 note: map list1’s strings to indices, sum both indices while scanning list2, and keep every string with the minimum sum

LeetCode 598 note: every operation covers the top-left corner, so the most-incremented cells form the intersection of all operations: min(a) × min(b)

LeetCode 594 note: subsequences need not be contiguous, so just count; for each x add the counts of x and x + 1

LeetCode 575 note: at most n / 2 candies can be eaten and at most len(set) kinds exist; the answer is the smaller of the two

LeetCode 566 note: return the original if the element counts differ; otherwise element k goes to (k // c, k % c)

LeetCode 561 note: sort and pair neighbors; each pair’s minimum is the element at an even index, so sum those

LeetCode 506 note: sort indices by score descending, give medals to the top three and rank strings to the rest, writing back into the original positions

LeetCode 500 note: make a set for each keyboard row and keep words whose lowercase character set is a subset of one row

LeetCode 495 note: each attack contributes min(gap to the next attack, duration), and the last one contributes the full duration

LeetCode 485 note: extend the current count on a 1, reset it on a 0, and keep the maximum

LeetCode 463 note: each land cell contributes 4 edges, minus 2 for each land neighbor above or to the left

LeetCode 455 note: sort children and cookies, satisfying the least greedy child with the smallest cookie that suffices; each pointer walks once