O(n) time

we declare a horizontal and vertical position variables (h,v)

we iterate over the string and of each change in each axis we add or subtract the value of the position in that axis.

assuming we start in (0,0) we will check if horizontal and vertical positions are equal and one of the is equal to zero

```
def judgeCircle(moves: String): Boolean = {
var h = 0
var v = 0
moves.foreach {
case 'U' => v = v + 1
case 'D' => v = v - 1
case 'L' => h = h + 1
case 'R' => h = h - 1
}
h == v && h == 0
}
```