LeetCode 657. 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

Solution:

/**
 * @param {string} moves
 * @return {boolean}
 */
var judgeCircle = function(moves) {
    var length = moves.length;
    var i = 0;
    var x = 0, y = 0;
    for(;i < length; i++) {
        var charac = moves.charAt(i);
        switch(charac) {
            case 'R':
                x = x + 1;
                break;
            case 'L':
                x = x - 1;
                break;
            case 'U':
                y = y - 1;
                break;
            case 'D':
                y = y + 1;
                break;
            default:
                break;
        }
    }
    if(x == 0 && y == 0) {
        return true;
    } 
    return false;
};