LeetCode: Divide Two Integers Solution

Approach

Use log identities (easy to understand)

1log(a/b) = log(c)
2=> log(a) - log(b) = log(c)
3=> e^(log(a) - log(b)) = c

Implementation

1/**
2 * @param {number} dividend
3 * @param {number} divisor
4 * @return {number}
5 */
6var divide = function (dividend, divisor) {
7  const MIN_INT = -Math.pow(2, 31)
8  const MAX_INT = Math.pow(2, 31) - 1
9  const sign = (dividend > 0) ^ (divisor > 0) ? -1 : 1
10
11  dividend = Math.abs(dividend)
12  divisor = Math.abs(divisor)
13
14  let res = Math.floor(Math.exp(Math.log(dividend) - Math.log(divisor)))
15  res *= sign
16  res = Math.min(res, MAX_INT)
17  res = Math.max(res, MIN_INT)
18
19  return res
20}