1464. Maximum Product of Two Elements in an Array

Description

Given the array of integers nums, you will choose two different indices i and j of that array. Return the maximum value of (nums[i]-1)*(nums[j]-1).

 

Example 1:

Input: nums = [3,4,5,2]
Output: 12 
Explanation: If you choose the indices i=1 and j=2 (indexed from 0), you will get the maximum value, that is, (nums[1]-1)*(nums[2]-1) = (4-1)*(5-1) = 3*4 = 12. 

Example 2:

Input: nums = [1,5,4,5]
Output: 16
Explanation: Choosing the indices i=1 and j=3 (indexed from 0), you will get the maximum value of (5-1)*(5-1) = 16.

Example 3:

Input: nums = [3,7]
Output: 12

 

Constraints:

• 2 <= nums.length <= 500
• 1 <= nums[i] <= 10^3

 

Solutions

Solution: Simulation

• Time complexity: O(n)
• Space complexity: O(1)

 

JavaScript

/**
 * @param {number[]} nums
 * @return {number}
 */
const maxProduct = function (nums) {
  let max = 0;
  let second = 0;

  for (const num of nums) {
    if (num > max) {
      second = max;
      max = num;
    } else if (num > second) {
      second = num;
    }
  }

  return (max - 1) * (second - 1);
};