Program to add two polynomials

<script>

// Simple JavaScript program to add two
// polynomials
// A utility function to return maximum 
// of two integers

// A[] represents coefficients of first polynomial
// B[] represents coefficients of second polynomial
// m and n are sizes of A[] and B[] respectively
  function add(A, B, m, n){
      let size = Math.max(m, n);
      var sum = [];
      for (var i = 0; i < 10; i++) sum[i] = 0;
      // Initialize the product polynomial
      for(let i = 0;i<m;i++){ 
          sum[i] = A[i];
      }

      // Take ever term of first polynomial
      for (let i = 0;i<n;i++){
          sum[i] += B[i];
      }
      return sum;
  }

  // A utility function to print a polynomial
  function printPoly(poly, n){
      let ans = '';
      for(let i = 0;i<n;i++){
          ans += poly[i];
          if (i != 0){
              ans +="x^ ";
              ans +=i;
           }
          if (i != n - 1){
              ans += " + ";
          }
       }
       document.write(ans);
  }
  // Driver Code
  
  // The following array represents
  // polynomial 5 + 10x^2 + 6x^3
  let A = [5, 0, 10, 6];
  // The following array represents
  // polynomial 1 + 2x + 4x^2
  let B = [1, 2, 4];
  let m = A.length;
  let n = B.length;

  document.write("First polynomial is" + "</br>");
  printPoly(A, m);
  document.write("</br>");
  document.write("Second polynomial is"  + "</br>");
  printPoly(B, n);
  let sum = add(A, B, m, n);
  let size = Math.max(m, n);
  document.write("</br>");
  document.write("sum polynomial is" + "</br>");
  printPoly(sum, size);
  
</script>

// Program to add two polynomials represented
// in linkedlist using recursion

// Node class
class Node {
  constructor(coeff, power) {
    this.coeff = coeff;
    this.power = power;
    this.next = null;
  }
}

// Function to add polynomials
function addPolynomials(head1, head2) {
  // Checking if our list is empty
  if (head1 === null && head2 === null) {
    return;
  }

  // List contains elmements
  else if (head1.power === head2.power) {
    console.log(` ${head1.coeff + head2.coeff}x^${head1.power} `);
    addPolynomials(head1.next, head2.next);
  } else if (head1.power > head2.power) {
    console.log(` ${head1.coeff}x^${head1.power} `);
    addPolynomials(head1.next, head2);
  } else {
    console.log(` ${head2.coeff}x^${head2.power} `);
    addPolynomials(head1, head2.next);
  }
}

function insert(head, coeff, power) {
  const new_node = new Node(coeff, power);
  while (head.next !== null) {
    head = head.next;
  }
  head.next = new_node;
}

function printList(head) {
  console.log("Linked List");
  while (head !== null) {
    console.log(` ${head.coeff}x^${head.power}`);
    head = head.next;
  }
}

// Main function
const head = new Node(5, 2);
insert(head, 4, 1);
const head2 = new Node(6, 2);

insert(head2, 4, 1);
printList(head);

console.log();
printList(head2);

console.log("\nAddition:\n");
addPolynomials(head, head2);

function addPolynomials(p1, p2) {
  let len1 = p1.length;
  let len2 = p2.length;
  
  if (len1 < len2) {
    p1 = p1.concat(new Array(len2 - len1).fill(0));
  } else {
    p2 = p2.concat(new Array(len1 - len2).fill(0));
  }
  
  let result = new Array(len1);
  for (let i = 0; i < len1; i++) {
    result[i] = p1[i] + p2[i];
  }
  
  return result;
}

let p1 = [2, 0, 4, 6, 8];
let p2 = [0, 0, 1, 2];

let result = addPolynomials(p1, p2);
console.log(result.join(" "));