Maximum Product of Two Elements in an Array - Easy - LeetCode

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

Solution:

using System;
using System.Collections.Generic;
using System.Text;

namespace LeetCode.AskGif.Easy.Array
{
 public class MaxProductSoln
 {
 public int MaxProduct(int[] nums)
 {
 int val = 0;
 int max = int.MinValue;
 for (int i = 0; i < nums.Length-1; i++)
 {
 for (int j = i+1; j < nums.Length; j++)
 {
 val = (nums[i] - 1) * (nums[j] - 1);
 if (val > max)
 {
 max = val; 
 }
 }
 }

 return max;
 }
 }
}

Time Complexity: O(n^2)

Space Complexity: O(1)

Unit Tests:

using LeetCode.AskGif.Easy.Array;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.Text;

namespace CodingUnitTest.Easy.Array
{
 [TestClass]
 public class MaxProductSolnTests
 {
 [TestMethod]
 public void MaxProductSoln_First()
 {
 var nums = new int[] { 3, 4, 5, 2 };
 var output = 12;
 var res = new MaxProductSoln().MaxProduct(nums);

 Assert.AreEqual(res, output);
 }

 [TestMethod]
 public void MaxProductSoln_Second()
 {
 var nums = new int[]{1, 5, 4, 5};
 var output = 16;
 var res = new MaxProductSoln().MaxProduct(nums);

 Assert.AreEqual(res, output);
 }

 [TestMethod]
 public void MaxProductSoln_Third()
 {
 var nums = new int[]{3, 7};
 var output = 12;
 var res = new MaxProductSoln().MaxProduct(nums);

 Assert.AreEqual(res, output);
 }
 }
}