Easy

LeetCode 492 note: search the width downward from √area; the first divisor of area gives the most square-like rectangle

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

LeetCode 482 note: remove every dash and uppercase first, then cut groups of k from the end so only the first group may be shorter

LeetCode 476 note: build an all-ones mask as long as num; num ^ mask is the complement

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

LeetCode 461 note: each 1 in x ^ y is a differing bit, so count the ones

LeetCode 459 note: s is a repetition of a substring exactly when s occurs in s + s with its first and last characters removed

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

LeetCode 448 note: use the array itself as the hash table, marking nums[x - 1] negative for each x; positions still positive are the missing numbers

LeetCode 441 note: find the largest k with k(k + 1) / 2 <= n; when moving right write l = mid + 1 or the search gets stuck

LeetCode 434 note: split() with no argument ignores extra spaces, so the number of pieces is the answer

LeetCode 415 note: add digit by digit from the ends with two pointers, tracking the carry, and append any leftover carry after the loop