String

LeetCode 67 note: add from the ends of both strings digit by digit, with carry sum // 2 and digit sum % 2

LeetCode 58 note: split() with no argument ignores trailing spaces; return the length of the last word

LeetCode 28 note: try matching needle at every start, or use str.find; index raises when not found

LeetCode 14 note: bound by the shortest string and check each position across all strings; the first mismatch gives the answer’s length

LeetCode 13 note: add each symbol’s value left to right, subtracting instead when it is smaller than the symbol to its right