Judge Route Circle

Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which means it moves back to the original place.

The move sequence is represented by a string. And each move is represent by a character. The valid robot moves are R (Right), L(Left), U (Up) and D (down). The output should be true or false representing whether the robot makes a circle.

Example 1:

Input: "UD"
Output: true

Example 2:

Input: "LL"
Output: false

class Solution {
    public boolean judgeCircle(String moves) {
        if(moves == null || moves.length() == 0)
            return true;
        int upOrDown = 0;
        int leftOrRight = 0;
        for(int i = 0; i < moves.length(); i++){
            switch (moves.charAt(i)){
                case 'U':
                    upOrDown ++;
                    break;
                case 'D':
                    upOrDown --;
                    break;
                case 'L':
                    leftOrRight --;
                    break;
                case 'R':
                    leftOrRight ++;
                    break;
            }
        }
        return (upOrDown == 0 && leftOrRight == 0);
    }
}