LeetCode

LeetCode 16 note: sort, fix one number, and find the other two with converging pointers, comparing the distance abs(sum - target)

LeetCode 15 note: sort, fix the first number, and find the other two with converging pointers, skipping equal values at all three positions to avoid duplicate triplets

LeetCode 11 note: start pointers at both ends and always move the shorter side; moving the taller side only narrows the width without raising the height

LeetCode 1189 note: each letter supports count // needed balloons, with l and o needed twice; take the minimum

LeetCode 1184 note: a circular route has two directions; clockwise is the sum between start and destination, counterclockwise is the total minus that

LeetCode 1160 note: a word is formable when none of its character counts exceeds chars’; sum the lengths of such words

LeetCode 1137 note: like Fibonacci, roll three variables; watch the base values T0 = 0, T1 = T2 = 1 and the loop range

LeetCode 1128 note: normalize each domino to (small, large) as a key and count; a key with c dominoes yields c(c - 1) / 2 pairs

LeetCode 1122 note: count first, emit values in arr2’s order, then append the remaining values in ascending order

LeetCode 1108 note: replace every . with [.]

LeetCode 1103 note: simulate the rounds, giving i + 1 candies on the i-th turn, and hand all the rest to the current person when short

LeetCode 1089 note: count the zeros to know each value’s shift, then move from back to front, writing the extra 0 when copying a zero