Codefights

A way to improve your programming skills.

View on GitHub

Addition Without Carrying

Description

A little boy is studying arithmetics. He has just learned how to add two integers, written one below another, column by column. But he always forgets about the important part - carrying.

Given two integers, your task is to find the result which the little boy will get.

Note: The boy had learned from this site, so feel free to check it out too if you are not familiar with column addition.

Example

For param1 = 456 and param2 = 1734, the output should be additionWithoutCarrying(param1, param2) = 1180.

   456
  1734

  • __
      1180 </code>

The boy performs the following operations from right to left:

  • 6 + 4 = 10 but he forgets about carrying the 1 and just writes down the 0 in the last column
  • 5 + 3 = 8
  • 4 + 7 = 11 but he forgets about the leading 1 and just writes down 1 under 4 and 7.
  • There is no digit in the first number corresponding to the leading digit of the second one, so the boy imagines that 0 is written before 456. Thus, he gets 0 + 1 = 1.

Input/Output

  • [execution time limit] 4 seconds (js)

  • [input] integer param1

    A non-negative integer.

    Guaranteed constraints:
    0 \leq param1 \le 10^5.

  • [input] integer param1

    A non-negative integer.

    Guaranteed constraints:
    0 \leq param2 \le 6 · 10^4.

  • [output] integer

    • The result that the little boy will get by using column addition without carrying.

[JavaScript (ES6)] Syntax Tips

1
2
3
4
5
6

// Prints help message to the console
// Returns a string
function helloWorld(name) {
console.log("This prints to the console when you Run Tests");
return "Hello, " + name;
}

Solution

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

function additionWithoutCarrying(param1, param2) {
  param1 = String(param1);
  param2 = String(param2);
  var a = param1.length > param2.length ? param1 : param2;
  var b = param1.length > param2.length ? param2 : param1;

  b = ("00000" + b)
    .slice(-a.length)
    .split("")
    .map(Number);
  a = a.split("").map(Number);

  var c = a.map((el, i) => (el + b[i]) % 10);
  return Number(c.join(""));
}