657. Judge Route Circle 判断线路成圆

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:
    def judgeCircle(self, moves):
        """
        :type moves: str
        :rtype: bool
        """
        res = [0,0]
        def o(s):
            if s == "L":
                res[0] = res[0] - 1
            elif s == "R":
                res[0] = res[0] + 1
            elif s == "U":
                res[1] = res[1] + 1
            elif s == "D":
                res[1] = res[1] - 1
        for i in range(0,len(moves)):
            o(moves[i])
        
        return res[0] == res[1] == 0

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