String

LeetCode 925 note: one pointer each over name and typed; every typed character either matches the next name character or repeats the previous typed character

LeetCode 917 note: two pointers each skip non-letters and swap when both point at letters; convert the string to a list first

LeetCode 884 note: count words across both sentences together; those appearing exactly once are the answer

LeetCode 859 note: lengths must match; identical strings need a repeated character; otherwise exactly two positions differ and cross-match

LeetCode 844 note: simulate backspaces with a stack; for O(1) space, walk from the end and count how many characters each # skips

LeetCode 824 note: split into words and convert each: move a leading consonant to the end, then append ma and i + 1 copies of a

LeetCode 821 note: one left-to-right pass for the distance to the nearest c on the left, then a right-to-left pass taking the minimum

LeetCode 819 note: replace punctuation with spaces, lowercase, split, count, and pick the most frequent word not banned

LeetCode 806 note: simulate writing, wrapping when the next letter would exceed 100; landing exactly on 100 stays on the line

LeetCode 804 note: translate each word into a Morse string and count the distinct results with a set

LeetCode 796 note: goal is a rotation of s exactly when the lengths match and goal occurs in s + s

LeetCode 771 note: put jewels in a set and count how many stones are in it