Hackerrank's miniMaxSum JavaScript Solution

Hey 👋🏽

This is a solution in response to this problem solving problem from hackerrank:

Given five positive integers, find the minimum and maximum values that can be calculated by summing exactly four of the five integers. Then print the respective minimum and maximum values as a single line of two space-separated long integers.

Example

arr = [1,3,5,7,9]

The minimum sum is and the maximum sum is 1 + 3 + 5 + 7 = 16. The function prints

16 24

Function Description

Complete the miniMaxSum function in the editor below.

miniMaxSum has the following parameter(s):

• arr: an array of integers

Print

Print two space-separated integers on one line: the minimum sum and the maximum sum of 4 of 5 elements.

Input Format

A single line of five space-separated integers.

Constraints

1<=arr[i]<=109

Output Format

Print two space-separated long integers denoting the respective minimum and maximum values that can be calculated by summing exactly four of the five integers. (The output can be greater than a 32 bit integer.)

Sample Input

1 2 3 4 5

Sample Output

10 14

Explanation

The numbers are 1 ,2 ,3 ,4 and 5. Calculate the following sums using four of the five integers:

1. Sum everything except 1, the sum is 2 + 3 + 4 + 5 = 14.
2. Sum everything except 2, the sum is 1 + 3 + 4 + 5 = 13.
3. Sum everything except 3, the sum is 1 + 2 + 4 + 5 = 12.
4. Sum everything except 4, the sum is 1 + 2 + 3 + 5 = 11.
5. Sum everything except 5, the sum is 1 + 2 + 3 + 4 = 10.

My approach:

• Add all array elements using reduce.
• Subtract from the sum the minimum value in the array. This get the maximum sum.
• Subtract from the sum the maximum value in the array. This get the minimum sum.

function miniMaxSum(arr) {
  let sum = arr.reduce((a, b) => {
    return a + b;
  });
  const min = sum - Math.max(...arr);
  const max = sum - Math.min(...arr);
  console.log(min + " " + max);
}

Thanks for reading 🥰.

Comments

[Oscar González]

Thanks for your solution. Here is another approach:

function miniMaxSum(arr) {
    arr.sort()
    let minimum = 0;
    let maximun = 0;
    for (let i=1; i< arr.length; i++){
        maximun += arr[i]
    }
    for (let i=0; i< arr.length -1; i++){
        minimum += arr[i]
    }
    console.log(`${minimum} ${maximun}`)  
}

[Christian barillas]

why did you use arr.sort() ? would you like to explain it for me please🙏🏻

[Mwafrika Josué]

This is really a good tutorial. it simplifies things and has a very good reasoning

[Brenda Haight]

Thank you everyone for the solution, I would like to share another approach:

function miniMaxSum(arr) {
arr.sort((a, b) => a - b);

const minSum = arr[0] + arr[1] + arr[2] + arr[3];

const maxSum = arr[1] + arr[2] + arr[3] + arr[4];

console.log(minSum, maxSum);
}

[Jorge "Chiro" Nuñez Delgado]

I think this not is a good approach, because if you doing the time complexity of this function is huge, practically you are traversing the array 3 times, in reduce, Math.max and Math.min function, that's mean 0(n) x 3. My approach is this:

miniMaxSum(arr) {
let vector = [-1, Number.MAX_SAFE_INTEGER];
let sum = 0;

for(let i = 0; i < arr.length - 1; i++) {

    sum += arr[i];

    if(arr[i] > vector[0])
    {
        vector[0] = arr[i];
    }

    if(arr[i] < vector[1])
    {
        vector[1] = arr[i];
    }
}

console.log((sum - vector[0]) + " " + (sum - vector[1]));

}