SpaceDrone | Topcoder Archive

Problem Statement

Our unmanned space vehicle responds to command sequences where each command is a single uppercase character that describes an action relative to the current location and orientation of the drone:

F -- move forward one unit
Y -- yaw 90 degrees counterclockwise as seen from the top of the drone
R -- roll 90 degrees counterclockwise as seen from the back of the drone

Y causes a rotation around the axis through the top and bottom of the drone. R causes a rotation around the axis through the back and front of the drone. Initially the drone is located at x=0,y=0,z=0. It is oriented so that its back-to-front axis is in the positive x direction, and its bottom to top axis is in the positive y direction. Create a class SpaceDrone that contains a method whereAmI that takes a command sequence as input and returns the x coordinate of the resulting position.

Definition

Class:: SpaceDrone
Method:: whereAmI
Parameters:: String
Returns:: int
Method signature:: int whereAmI(String commands)
(be sure your method is public)

Notes

Notice that the orientation of the xyz coordinate system is irrelevant since you only need to return the final x coordinate.

Constraints

commands contains between 1 and 50 characters inclusive
each character in commands is uppercase F, Y, or R

Examples

```
"FFF"
```
```
Returns: 3
```
The drone goes forward along the x axis 3 units, ending at (3,0,0)
```
"YYRRYRY""
```
```
Returns: 0
```
The drone has done multiple rotations, but has never moved from (0,0,0)
```
"YFYFY"
```
```
Returns: -1
```
```
"YFRRYFFFY"
```
```
Returns: 3
```

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