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.

题目大意：
初始位于坐标(0, 0)，UDLR分别表示向上下左右移动，求移动结束后是否位于原点。

Example 1:

Input: "UD"
Output: true

Example 2:

Input: "LL"
Output: false

code:

    func judgeCircle(_ moves: String) -> Bool {
        var x = 0,y = 0
        for m in moves.characters{
            if m == "U" {
                y += 1
            }else if(m == "D"){
                y -= 1
            }else if(m == "L"){
                x -= 1
            }else if(m == "R"){
                x += 1
            }
        }
        if x == 0 && y == 0 {
            return true
        }
        
        return false
    }

test code:

print(judgeCircle("LLRRU"))