Robot Return to Origin
There is a robot starting at the position (0, 0), the origin, on a 2D plane. Given a sequence of its moves, judge if this robot ends up at (0, 0) after it completes its moves.
You are given a string moves that represents the move sequence of the robot where moves[i] represents its i^th move. Valid moves are 'R' (right), 'L' (left), 'U' (up), and 'D' (down).
Return true if the robot returns to the origin after it finishes all of its moves, or false otherwise.
Note: The way that the robot is "facing" is irrelevant. 'R' will always make the robot move to the right once, 'L' will always make it move left, etc. Also, assume that the magnitude of the robot's movement is the same for each move.
Example 1
Input
moves = "UD"Output
trueThe robot moves up once, and then down once, so it ended up at the origin where it started.
Example 2
Input
moves = "LL"Output
falseThe robot moves left twice, so it is not at the origin at the end of its moves.
Constraints
- 1 <= moves.length <= 2 * 10^4
- moves only contains the characters 'U', 'D', 'L' and 'R'.