[Solved] algorithm to find the number of boxes needed for different lengths of cable [closed]

by 


Set L = sum of lengths
While L > 0
  Get largest box B where size S <= L OR smallest box
  set numB = Floor division L / B OR 1
  store numB of B
  Subtract numB * B from L

you’ll need some adjustments for a case where you might have waste (ie need 4 feet of cable but smallest box is 5)

if I were to javascript it:

function getBoxes(lengths, boxes) {
   // sort descending
   boxes = boxes.sort((b1, b2) => b2 - b1); 
   // get the smallest box (needed later)
   const minB = boxes[boxes.length - 1]; 
   // create an object to store my results;
   const boxResult = boxes.reduce((acc, b) => Object.assign(acc, {[b]: 0}), {});
   // sum lengths
   let L = lengths.reduce((sum, l) => sum += l, 0);
   while (L > 0) {
      // get first box less than or equal to L or smallest box
      const B = boxes.find(b => b <= L) || minB;
      // get floor division or 1
      const numB = Math.floor(L / B) || 1;
      // store that number of that box (adding for waste case)
      boxResult[B] += numB;
       // subtract from L
      L -= numB * B;
   }
   // done
   return boxResult;
}

const lengths = [1, 1, 2, 3, 4, 5, 6, 7, 5, 4, 3, 2];
const boxes = [10, 5, 20];

const result = getBoxes(lengths, boxes);
console.log(result);

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solved algorithm to find the number of boxes needed for different lengths of cable [closed]