LeetCode：657. Judge Route Circle

最新推荐文章于 2022-08-11 19:15:14 发布

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本文介绍了一种通过分析机器人移动序列来判断它是否能回到初始位置的方法。利用字典映射或条件语句实现，针对不同的移动指令进行计算，最终确定机器人是否形成了闭环。

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链接：
https://leetcode.com/problems/judge-route-circle/description/

题目：
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

思路：
dict或者elif

Answer：
dict

class Solution:
    def judgeCircle(self, moves):
        """
        :type moves: str
        :rtype: bool
        """
        table = {
            'R': 1,
            'L': -1,
            'U': 1.5,
            'D': -1.5
        }
        sum = 0
        for move in moves:
            sum += table[move]
        return sum==0

elif

class Solution(object):
    def judgeCircle(self, moves):
        x = y = 0
        for move in moves:
            if move == 'U': y -= 1
            elif move == 'D': y += 1
            elif move == 'L': x -= 1
            elif move == 'R': x += 1

        return x == y == 0