
# Add Strings

## Dscription

[doc](https://leetcode.com/problems/add-strings/)

## Solutions

### First Idea

```javascript
/**
 * @param {string} num1
 * @param {string} num2
 * @return {string}
 */
var addStrings = function (num1, num2) {
  let k = (curry = 0)

  let nums = []
  let i = num1.length
  let j = num2.length

  while (i > 0 || j > 0) {
    const sum = +(num1[--i] ?? 0) + +(num2[--j] ?? 0) + curry
    curry = Math.floor(sum / 10)
    nums[k++] = sum % 10
  }

  if (curry) {
    nums[k] = curry
  }

  return nums.reverse().join('')
}
```

- Time Complexity: O(n)
- Space Complexity: O(n)
