Find sum of largest repeated number in an array javascript

Question

I am trying to find largest repeated number in an array and summation of it.

While going through here , I found the solution to find max number. But now I need to count how many max(largest) number is there and store number of maximum number and then summation.

Example:- array- [5,5,7,9,9,9] . So max number is 9 and it is 3 times so , it will store in another array [9,9,9] and total = 27.

I got this to find max number in an array:-

function evaluate() {
  const input = prompt("Please enter the array of integers in the form: 1,2,3,1")
    .split(',')
    .map(nums => nums.trim());

  function max(numArray) 
{
    var nums = numArray.slice();
    if (nums.length == 1) { return nums[0]; }
    if (parseInt(nums[0]) < parseInt(nums[1])) { nums.splice(0,1); }
    else { nums.splice(1,1); }    
    return max(nums);
}


  if (input == "" || input == null) {
            document.writeln("Sorry, there is nothing that can be calculated."); 
        } else {    

  document.writeln("The largest number is: ");
  document.writeln(max(input) + " with a starting input string of: " + input);
}
}
evaluate();

So I want my final output to be shown is 27 from the above example.

it will store in another array Do you need another array, or do you really just want the 27? — CertainPerformance
– CertainPerformance, Commented May 21, 2018 at 9:03
Instead of using split+map+trim you could just use match(/\d+/g). There is also no need for parseInt in parseInt(nums[0]) < parseInt(nums[1]), you can use just nums[0] < nums[1] as relational expressions using < coerce both operands to number. — RobG
– RobG, Commented May 21, 2018 at 9:09

jspcal · Accepted Answer · 2018-05-21 09:23:24Z

4

This returns an object with the specified outputs {max: 9, items: [9,9,9], sum: 27}.

function maxElementSum(arr) {
    var max = Math.max(...arr)
    var count = arr.filter(el => el == max).length
    return {max: max, items: Array(count).fill(max), sum: max * count}
}

console.log(maxElementSum([5,5,7,9,9,9]))

edited May 21, 2018 at 9:23

answered May 21, 2018 at 9:10

jspcal

52k7 gold badges76 silver badges79 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

brk · Accepted Answer · 2018-05-21 09:10:40Z

1

Use Math.max to get the largest value and then use the filter & reduce to sum the value

// find the largest number
var _gt = Math.max(...[5, 5, 7, 9, 9, 9])
// then filter the array and get the largest values
// and use reduce to sum the numbers
var arr = [5, 5, 7, 9, 9, 9].filter(function(item) {
  return _gt === item
}).reduce(function(acc, curr) {
  acc += curr;
  return acc;

}, 0);
console.log(arr)

answered May 21, 2018 at 9:10

brk

50.3k10 gold badges59 silver badges85 bronze badges

Comments

Nina Scholz · Accepted Answer · 2018-05-21 09:11:36Z

1

You could count the values, reduce the max count and return the multiplication of value and count.

var array = [5, 5, 7, 9, 9, 9],
    max = Object
        .entries(
            array.reduce((r, v) => (r[v] = (r[v] || 0) + 1, r), Object.create(null))
        )
        .reduce((a, b) => a[1] > b[1] ? a : b)
        .reduce((a, b) => a * b);
    
console.log(max);

answered May 21, 2018 at 9:11

Nina Scholz

388k26 gold badges367 silver badges417 bronze badges

Comments

RobG · Accepted Answer · 2018-05-21 09:33:55Z

1

If you start with an array, then you only need reduce to both find the maximum value and to return the sum, e.g.

var nums = [5,5,7,9,9,9],
    max  = -Infinity,
    result = nums.reduce((acc, num) => num > max? acc = max = num : num == max? acc += num : acc, 0);

console.log('Result: ' + result);

answered May 21, 2018 at 9:33

RobG

148k32 gold badges180 silver badges216 bronze badges

Comments

dilip · Accepted Answer · 2018-05-21 09:34:23Z

1

You can do it easily just using one forEach loop in O(n) time,

var array = [5, 5, 7, 9, 9, 9];
var max = array[0], total = 0;
array.forEach((a)=>{
  if(a==max){
    total+=max;
  }
  else if(a>max){
    max = total = a;
  }
});
console.log("total:"+total);

answered May 21, 2018 at 9:34

dilip

515 bronze badges

Collectives™ on Stack Overflow

Find sum of largest repeated number in an array javascript

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related