657. Judge Route Circle(路线圈)

最新推荐文章于 2023-01-14 09:01:26 发布

原创最新推荐文章于 2023-01-14 09:01:26 发布 · 298 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#leetcode #c++ #python #string

【LeetCode】专栏收录该内容

103 篇文章

订阅专栏

本文介绍了一种通过解析移动指令序列来判断机器人是否能从原点出发后返回原点的方法。利用坐标变化处理移动指令，最终通过比较坐标是否为(0,0)来判断机器人是否回到了起点。

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

题意

判断从原点出发经过一系列操作，是否能回到原点。

题解

转换成坐标处理。

C++代码

class Solution {
public:
    bool judgeCircle(string moves) {
        /*(x,y)
        R (x+1,y), L (x-1,y), U (x, y+1) and D (x, y-1).
        */
        int x=0,y=0;
        for(int i=0; i<moves.length(); i++)
        {
            if(moves[i] == 'R') x+=1;
            if(moves[i] == 'L') x-=1;
            if(moves[i] == 'U') y+=1;
            if(moves[i] == 'D') y-=1;
        }
        return x==0&&y==0;
    }
};

python代码

class Solution(object):
    def judgeCircle(self, moves):
        """
        :type moves: str
        :rtype: bool
        """
        x=0
        y=0
        for i in range(0, len(moves)):
            if moves[i] == 'R':
                x+=1
            if moves[i] == 'L':
                x-=1
            if moves[i] == 'U':
                y+=1
            if moves[i] == 'D':
                y-=1

        return x==0  and y==0