python--leetcode657. 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

这题的意思就是一个机器人在（0,0）点，经过上下左右移动后是否回到原点。上下左右移动通过字符串操作。

代码：

class Solution(object):    def judgeCircle(self, moves):        """        :type moves: str        :rtype: bool        """        left_right=0        down_up=0        for i in range(len(moves)):            if(moves[i]=='R'):  left_right=left_right+1            if (moves[i] == 'L'):  left_right = left_right - 1            if(moves[i]=='U'):  down_up=down_up+1            if(moves[i]=='D'):  down_up=down_up-1        if(left_right==0 and down_up==0):return True        else: return Falses=Solution()print(s.judgeCircle("DURDLDRRLL"))

思路就是通过两个变量来判断是否最终状态是移动过了的。

当然还有更简单的一行解决的代码：

def judgeCircle(self, moves):    return moves.count('L') == moves.count('R') and moves.count('U') == moves.count('D')