Maximum Product of Three Numbers

Description

Given an integer array, find three numbers whose product is maximum and output the maximum product.

Example 1:

Input: [1,2,3]
Output: 6

 

Example 2:

Input: [1,2,3,4]
Output: 24

 

Note:

1. The length of the given array will be in range [3,10⁴] and all elements are in the range [-1000, 1000].
2. Multiplication of any three numbers in the input won't exceed the range of 32-bit signed integer.

 

Solution(javascript)

/**
 * @param {number[]} nums
 * @return {number}
 */
const maximumProduct = function (nums) {
  let min1 = Infinity
  let min2 = Infinity
  let max1 = -Infinity
  let max2 = -Infinity
  let max3 = -Infinity
  nums.forEach((num) => {
    if (num < min1) {
      min2 = min1
      min1 = num
    } else if (num < min2) {
      min2 = num
    }
    if (num > max1) {
      max3 = max2
      max2 = max1
      max1 = num
    } else if (num > max2) {
      max3 = max2
      max2 = num
    } else if (num > max3) {
      max3 = num
    }
  })
  return Math.max(min1 * min2 * max1, max1 * max2 * max3)
}