题目描述：

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

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。

解题思路：

模拟题

Python代码：

class Solution(object):
    def judgeCircle(self, moves):
        """
        :type moves: str
        :rtype: bool
        """
        x = y = 0
        for m in moves:
            if m == 'U': y += 1
            elif m == 'D': y -= 1
            elif m == 'R': x += 1
            elif m == 'L': x -= 1
        return x == y == 0

下面的代码也可以

Python代码：

class Solution(object):
    def judgeCircle(self, moves):
        """
        :type moves: str
        :rtype: bool
        """
        return moves.count('L') == moves.count('R') and \
                moves.count('U') == moves.count('D')

 

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