minSum.js

// Introduction and Warm-up (Highly recommended)
// Playing With Lists/Arrays Series
// Task
// Given an array of integers , Find the minimum sum which is obtained from summing each Two integers product .

// Notes
// Array/list will contain positives only .
// Array/list will always has even size
// Input >> Output Examples
// minSum({5,4,2,3}) ==> return (22) 
// Explanation:
// The minimum sum obtained from summing each two integers product , 5*2 + 3*4 = 22
// minSum({12,6,10,26,3,24}) ==> return (342)
// Explanation:
// The minimum sum obtained from summing each two integers product , 26*3 + 24*6 + 12*10 = 342
// minSum({9,2,8,7,5,4,0,6}) ==> return (74)
// Explanation:
// The minimum sum obtained from summing each two integers product , 9*0 + 8*2 +7*4 +6*5 = 74
// Playing with Numbers Series
// Playing With Lists/Arrays Series
// For More Enjoyable Katas
// ALL translations are welcomed
// Enjoy Learning !!
// Zizou


function minSum(arr) {

    let sorted = arr.sort((a,b) => a-b);
    let sum = 0;

    for(let i = 0; i < sorted.length/2; i++){

        sum += sorted[i] * sorted[sorted.length - i - 1];

    }

    return sum;  
  
}



console.log(minSum([12,6,10,26,3,24]));

//cw's

function minSum2(arr) {
    return arr.sort( (a,b) => a-b )
              .slice(0, arr.length/2)
              .reduce( (acc,curr,index) => acc += curr * arr[ arr.length - index - 1 ], 0 )
  }


  function minSum3(arr) {
    arr.sort((x,y)=>x-y)
    s=0
    while(arr.length)s+=arr.pop()*arr.shift()
    return s
  }


  function minSum4(a) {
    return a.sort((a,b)=>a-b).reduce((s,x,i,a)=>s+x*a[a.length-i-1],0)/2
  }